fix(migrate): restore storage object xattrs lost in the server move

After the netralax.cloud -> netralax.de migration every storage object GET
returned HTTP 500 (ENODATA "The extended attribute does not exist"). Root
cause: the object bytes were copied but Supabase Storage (file backend,
v1.48.26) keeps each object's response metadata in Linux xattrs
(user.supabase.{content-type,cache-control,etag}); the copy did not preserve
them. The old server is gone, but the values survive in storage.objects.metadata,
so this script reconstructs the xattrs from the DB. Verified: public avatar GETs
went 500 -> 200 after running it; all 18 objects (avatars, banner, attachments)
restored, 0 files genuinely missing. Idempotent, touches no object bytes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/desktop/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@chat-app/desktop",
-  "version": "0.21.5",
+  "version": "0.21.11",
   "private": true,
   "description": "Electron desktop client (Windows / macOS / Linux)",
   "type": "module",
@@ -24,6 +24,7 @@
     "@livekit/components-react": "^2.9.0",
     "@livekit/track-processors": "^0.7.2",
     "@supabase/supabase-js": "^2.46.0",
+    "@tanstack/react-virtual": "^3.10.0",
     "better-sqlite3": "^11.3.0",
     "canvas-confetti": "^1.9.4",
     "electron-updater": "^6.3.0",
@@ -35,7 +36,6 @@
     "react-easy-crop": "^5.5.7",
     "react-i18next": "^15.1.1",
     "react-router-dom": "^6.28.0",
-    "react-virtuoso": "^4.18.7",
     "zustand": "^5.0.1"
   },
   "devDependencies": {

apps/desktop/src/components/Avatar.tsx

@@ -1,6 +1,8 @@
 // Reusable avatar that prefers an uploaded image and falls back to a coloured
 // letter circle. Use this everywhere the app needs to render a profile.
 
+import { useEffect, useState } from 'react';
+
 import { useCachedAvatarUrl } from '../lib/avatarCache';
 
 interface Props {
@@ -27,7 +29,13 @@ export function Avatar({
   loading = 'lazy',
 }: Props) {
   const effectiveUrl = useCachedAvatarUrl(url);
-  if (effectiveUrl) {
+  // If the image URL is non-empty but unreachable (e.g. the storage object is
+  // missing / 404s), the bare <img> would render broken with no fallback.
+  // Track a load error and degrade to the letter circle instead. Reset on URL
+  // change so a fresh, valid avatar is retried.
+  const [failed, setFailed] = useState(false);
+  useEffect(() => setFailed(false), [effectiveUrl]);
+  if (effectiveUrl && !failed) {
     return (
       <img
         src={effectiveUrl}
@@ -35,6 +43,7 @@ export function Avatar({
         className={'shrink-0 rounded-full object-cover ' + className}
         draggable={false}
         loading={loading}
+        onError={() => setFailed(true)}
       />
     );
   }

apps/desktop/src/components/MessageList.tsx

@@ -0,0 +1,325 @@
+import { useVirtualizer } from '@tanstack/react-virtual';
+import {
+  forwardRef,
+  useCallback,
+  useEffect,
+  useImperativeHandle,
+  useLayoutEffect,
+  useRef,
+  useState,
+  type ReactNode,
+} from 'react';
+
+import { isNearBottom, isNearTop, nextStickIntent } from '../lib/scrollController';
+import type { VirtuosoRow } from '../pages/ConversationPage';
+
+export interface MessageListHandle {
+  scrollToBottom(behavior?: ScrollBehavior): void;
+  scrollToRow(index: number, align?: 'center' | 'end', behavior?: ScrollBehavior): void;
+}
+
+export interface MessageListProps {
+  rows: VirtuosoRow[];
+  renderRow: (index: number, row: VirtuosoRow) => ReactNode;
+  computeKey: (row: VirtuosoRow) => string;
+  /** Initial scroll target for a freshly-mounted list. */
+  initialAnchor: { type: 'bottom' } | { type: 'row'; index: number };
+  /** Reveal gate — the list stays hidden until reactions/heights are loaded, so
+   *  the post-paint height cascade is never visible. */
+  ready: boolean;
+  estimateRowHeight?: number;
+  atBottomThreshold?: number;
+  onReachTop?: () => void;
+  onAtBottomChange?: (atBottom: boolean) => void;
+  onTopRowChange?: (topIndex: number) => void;
+}
+
+export const MessageList = forwardRef<MessageListHandle, MessageListProps>(function MessageList(
+  {
+    rows,
+    renderRow,
+    computeKey,
+    initialAnchor,
+    ready,
+    estimateRowHeight = 64,
+    atBottomThreshold = 64,
+    onReachTop,
+    onAtBottomChange,
+    onTopRowChange,
+  },
+  ref,
+) {
+  const scrollElRef = useRef<HTMLDivElement>(null);
+  const [revealed, setRevealed] = useState(false);
+
+  // THE single source of truth: should the view stay pinned to the bottom?
+  // Only a genuine user up-input (wheel / key / touch / scrollbar drag) turns
+  // this OFF; only reaching the bottom turns it ON. A measurement reflow must
+  // never flip it — that was the root cause of the chat-switch bug.
+  const stickRef = useRef(true);
+  // Debounce for onAtBottomChange — fire the parent only on a real transition.
+  const lastReportedAtBottomRef = useRef<boolean | null>(null);
+  // Guard: scrolls WE cause (pin / measure re-pin / scrollToIndex) fire onScroll
+  // a tick later. Within this window we don't treat a scrollTop decrease as the
+  // user dragging up.
+  const programmaticRef = useRef(0);
+  // Previous scrollTop, to detect a genuine scrollbar/keyboard up-drag.
+  const lastScrollTopRef = useRef(0);
+  // Load-older preservation: remember the first row key + scrollHeight so a
+  // prepend can be detected and the viewport restored.
+  const prevFirstKeyRef = useRef<string | null>(null);
+  const prevScrollHeightRef = useRef(0);
+
+  // Latest onAtBottomChange, read through a ref so the input-listener effect
+  // can stay mounted once (deps []) without capturing a stale callback.
+  const onAtBottomChangeRef = useRef(onAtBottomChange);
+  onAtBottomChangeRef.current = onAtBottomChange;
+
+  const virtualizer = useVirtualizer({
+    count: rows.length,
+    getScrollElement: () => scrollElRef.current,
+    estimateSize: () => estimateRowHeight,
+    overscan: 8,
+    getItemKey: (index) => computeKey(rows[index]!),
+  });
+
+  const readMetrics = useCallback(() => {
+    const el = scrollElRef.current;
+    return el
+      ? { scrollTop: el.scrollTop, scrollHeight: el.scrollHeight, clientHeight: el.clientHeight }
+      : { scrollTop: 0, scrollHeight: 0, clientHeight: 0 };
+  }, []);
+
+  const pinToBottom = useCallback(() => {
+    const el = scrollElRef.current;
+    if (!el) return;
+    programmaticRef.current = performance.now();
+    el.scrollTop = el.scrollHeight;
+    lastScrollTopRef.current = el.scrollTop;
+  }, []);
+
+  // Report at-bottom to the parent only on a true transition, always driven by
+  // the INTENT (stickRef) — never the raw position. This is what kills the
+  // feedback loop: a transient "not at bottom" mid-reflow is never persisted.
+  const reportAtBottom = useCallback((atBottom: boolean) => {
+    if (lastReportedAtBottomRef.current === atBottom) return;
+    lastReportedAtBottomRef.current = atBottom;
+    onAtBottomChangeRef.current?.(atBottom);
+  }, []);
+
+  // A genuine user up-input: drop the stick intent immediately.
+  const markUserMovedUp = useCallback(() => {
+    if (!stickRef.current) return;
+    stickRef.current = false;
+    reportAtBottom(false);
+  }, [reportAtBottom]);
+
+  // Re-pin to the true bottom whenever the content (or viewport) resizes while
+  // sticking. ResizeObserver fires after layout / before paint, so as rows
+  // measure and the list grows the bottom stays pinned with no stale frame.
+  useEffect(() => {
+    const el = scrollElRef.current;
+    if (!el) return;
+    const ro = new ResizeObserver(() => {
+      const e = scrollElRef.current;
+      if (stickRef.current && e) {
+        programmaticRef.current = performance.now();
+        e.scrollTop = e.scrollHeight;
+        lastScrollTopRef.current = e.scrollTop;
+      }
+    });
+    ro.observe(el);
+    const inner = el.firstElementChild;
+    if (inner) ro.observe(inner);
+    return () => ro.disconnect();
+  }, []);
+
+  // Genuine-user-intent listeners. These are the ONLY way (besides reaching the
+  // bottom) the stick intent turns off, so a reflow can never unstick the list.
+  useEffect(() => {
+    const el = scrollElRef.current;
+    if (!el) return;
+    const onWheel = (e: WheelEvent) => {
+      if (e.deltaY < 0) markUserMovedUp();
+    };
+    const onKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'PageUp' || e.key === 'Home' || e.key === 'ArrowUp') markUserMovedUp();
+    };
+    let touchStartY = 0;
+    const onTouchStart = (e: TouchEvent) => {
+      touchStartY = e.touches[0]?.clientY ?? 0;
+    };
+    const onTouchMove = (e: TouchEvent) => {
+      const y = e.touches[0]?.clientY ?? 0;
+      // Finger dragged DOWN (content scrolls up toward older messages). Guard on
+      // scrollTop>0 so an overscroll bounce at the bottom doesn't unstick.
+      if (y - touchStartY > 8 && (scrollElRef.current?.scrollTop ?? 0) > 0) markUserMovedUp();
+    };
+    el.addEventListener('wheel', onWheel, { passive: true });
+    el.addEventListener('keydown', onKeyDown);
+    el.addEventListener('touchstart', onTouchStart, { passive: true });
+    el.addEventListener('touchmove', onTouchMove, { passive: true });
+    return () => {
+      el.removeEventListener('wheel', onWheel);
+      el.removeEventListener('keydown', onKeyDown);
+      el.removeEventListener('touchstart', onTouchStart);
+      el.removeEventListener('touchmove', onTouchMove);
+    };
+  }, [markUserMovedUp]);
+
+  // Deferred reveal: when ready, pin to the anchor and keep pinning each frame
+  // until the list height has SETTLED over two consecutive frames, THEN reveal —
+  // so what appears is already at its final position with no top-then-jump.
+  useLayoutEffect(() => {
+    if (!ready || revealed || rows.length === 0) return;
+    const el = scrollElRef.current;
+    if (!el) return;
+    const rowIdx = Math.max(
+      0,
+      Math.min(initialAnchor.type === 'row' ? initialAnchor.index : 0, rows.length - 1),
+    );
+    if (initialAnchor.type === 'bottom') {
+      stickRef.current = true;
+      pinToBottom();
+    } else {
+      stickRef.current = false;
+      programmaticRef.current = performance.now();
+      virtualizer.scrollToIndex(rowIdx, { align: 'start' });
+    }
+    reportAtBottom(stickRef.current);
+
+    let prevSH = -1;
+    let stableFrames = 0;
+    const settle = (attempts: number): void => {
+      const e = scrollElRef.current;
+      if (!e) {
+        setRevealed(true);
+        return;
+      }
+      programmaticRef.current = performance.now();
+      if (stickRef.current) {
+        e.scrollTop = e.scrollHeight;
+        lastScrollTopRef.current = e.scrollTop;
+      } else {
+        virtualizer.scrollToIndex(rowIdx, { align: 'start' });
+      }
+      const sh = e.scrollHeight;
+      // Require TWO consecutive stable-height frames: a single stable frame can
+      // land mid-cascade (between reactions and the unread divider measuring)
+      // and reveal a not-yet-final layout that then jumps.
+      stableFrames = sh === prevSH ? stableFrames + 1 : 0;
+      prevSH = sh;
+      if (stableFrames >= 2 || attempts <= 0) {
+        setRevealed(true);
+      } else {
+        requestAnimationFrame(() => settle(attempts - 1));
+      }
+    };
+    requestAnimationFrame(() => settle(12));
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [ready, rows.length]);
+
+  // Load-older preservation: if rows were prepended (first key changed and the
+  // user is near the top), restore scrollTop by the height delta so the viewport
+  // stays put instead of jumping.
+  useLayoutEffect(() => {
+    const firstKey = rows.length > 0 ? computeKey(rows[0]!) : null;
+    const el = scrollElRef.current;
+    if (el && revealed && prevFirstKeyRef.current && firstKey !== prevFirstKeyRef.current) {
+      const delta = el.scrollHeight - prevScrollHeightRef.current;
+      if (delta > 0 && el.scrollTop < atBottomThreshold * 4) {
+        el.scrollTop += delta;
+        lastScrollTopRef.current = el.scrollTop;
+      }
+    }
+    prevFirstKeyRef.current = firstKey;
+    prevScrollHeightRef.current = el?.scrollHeight ?? 0;
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [rows]);
+
+  // Re-pin on any rows change while sticking. Covers the two-phase data swap
+  // (the cached array is replaced by the freshly-decrypted one ~100ms after
+  // reveal) which the ResizeObserver can miss when the new content happens to
+  // measure to the same height.
+  useLayoutEffect(() => {
+    if (revealed && stickRef.current) pinToBottom();
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [rows]);
+
+  const handleScroll = useCallback(() => {
+    const m = readMetrics();
+    const programmatic = performance.now() - programmaticRef.current < 120;
+    const nearBottom = isNearBottom(m, atBottomThreshold);
+    // A scrollbar drag or keyboard scroll surfaces here as a scrollTop decrease.
+    // Suppress it inside the programmatic window so our own re-pin / settle is
+    // never mistaken for the user moving up. 2px deadzone absorbs sub-pixel jitter.
+    const userMovedUp = !programmatic && m.scrollTop < lastScrollTopRef.current - 2;
+    lastScrollTopRef.current = m.scrollTop;
+
+    stickRef.current = nextStickIntent(stickRef.current, { nearBottom, userMovedUp });
+    reportAtBottom(stickRef.current);
+
+    if (isNearTop(m, atBottomThreshold * 4)) onReachTop?.();
+    const first = virtualizer.getVirtualItems()[0];
+    if (first) onTopRowChange?.(first.index);
+  }, [atBottomThreshold, onReachTop, onTopRowChange, readMetrics, reportAtBottom, virtualizer]);
+
+  useImperativeHandle(
+    ref,
+    () => ({
+      scrollToBottom: () => {
+        stickRef.current = true;
+        reportAtBottom(true);
+        pinToBottom();
+      },
+      scrollToRow: (index, align = 'center') => {
+        // The user is jumping to a specific row — drop the stick intent first so
+        // the ResizeObserver doesn't immediately drag the target back to the bottom.
+        stickRef.current = false;
+        reportAtBottom(false);
+        programmaticRef.current = performance.now();
+        virtualizer.scrollToIndex(index, { align });
+      },
+    }),
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+    [virtualizer, rows.length, reportAtBottom, pinToBottom],
+  );
+
+  const items = virtualizer.getVirtualItems();
+
+  return (
+    <div
+      ref={scrollElRef}
+      onScroll={handleScroll}
+      tabIndex={0}
+      className="min-h-0 flex-1 overflow-y-auto"
+      style={{
+        opacity: revealed ? 1 : 0,
+        position: 'relative',
+        overflowAnchor: 'none',
+        outline: 'none',
+      }}
+    >
+      <div style={{ height: virtualizer.getTotalSize(), position: 'relative', width: '100%' }}>
+        {items.map((vi) => (
+          <div
+            key={vi.key}
+            data-index={vi.index}
+            ref={virtualizer.measureElement}
+            style={{
+              position: 'absolute',
+              top: 0,
+              left: 0,
+              width: '100%',
+              transform: `translateY(${vi.start}px)`,
+            }}
+          >
+            {renderRow(vi.index, rows[vi.index]!)}
+          </div>
+        ))}
+      </div>
+      {/* 12px bottom breathing space (matches the old Virtuoso Footer). */}
+      <div style={{ height: 12 }} />
+    </div>
+  );
+});

apps/desktop/src/lib/scrollController.test.ts

@@ -0,0 +1,73 @@
+import { describe, expect, it } from 'vitest';
+
+import { isNearBottom, isNearTop, nextStickIntent, resolveInitialAnchor } from './scrollController';
+
+const m = (scrollTop: number, scrollHeight: number, clientHeight: number) => ({
+  scrollTop,
+  scrollHeight,
+  clientHeight,
+});
+
+describe('isNearBottom', () => {
+  it('true exactly at the bottom', () => {
+    expect(isNearBottom(m(900, 1000, 100), 64)).toBe(true);
+  });
+  it('true within threshold', () => {
+    expect(isNearBottom(m(860, 1000, 100), 64)).toBe(true);
+  });
+  it('false beyond threshold', () => {
+    expect(isNearBottom(m(800, 1000, 100), 64)).toBe(false);
+  });
+});
+
+describe('isNearTop', () => {
+  it('true at top', () => {
+    expect(isNearTop(m(0, 1000, 100), 64)).toBe(true);
+  });
+  it('false past threshold', () => {
+    expect(isNearTop(m(200, 1000, 100), 64)).toBe(false);
+  });
+});
+
+describe('resolveInitialAnchor', () => {
+  it('anchors to last row at end by default (no saved position)', () => {
+    expect(resolveInitialAnchor(null, 50)).toEqual({ index: 49, align: 'end' });
+  });
+  it('anchors to bottom when saved position stuck to bottom', () => {
+    expect(resolveInitialAnchor({ topmostIndex: 10, stickToBottom: true }, 50)).toEqual({
+      index: 49,
+      align: 'end',
+    });
+  });
+  it('restores the saved row at the top when scrolled up', () => {
+    expect(resolveInitialAnchor({ topmostIndex: 12, stickToBottom: false }, 50)).toEqual({
+      index: 12,
+      align: 'start',
+    });
+  });
+  it('clamps a stale saved index to the current row count', () => {
+    expect(resolveInitialAnchor({ topmostIndex: 999, stickToBottom: false }, 50)).toEqual({
+      index: 49,
+      align: 'start',
+    });
+  });
+  it('handles an empty list', () => {
+    expect(resolveInitialAnchor(null, 0)).toEqual({ index: 0, align: 'end' });
+  });
+});
+
+describe('nextStickIntent', () => {
+  it('turns ON when the bottom is reached', () => {
+    expect(nextStickIntent(false, { nearBottom: true, userMovedUp: false })).toBe(true);
+  });
+  it('turns OFF when the user genuinely moves up', () => {
+    expect(nextStickIntent(true, { nearBottom: false, userMovedUp: true })).toBe(false);
+  });
+  it('keeps the previous intent on a neutral scroll (measurement reflow)', () => {
+    expect(nextStickIntent(true, { nearBottom: false, userMovedUp: false })).toBe(true);
+    expect(nextStickIntent(false, { nearBottom: false, userMovedUp: false })).toBe(false);
+  });
+  it('reaching the bottom wins over a simultaneous move-up signal', () => {
+    expect(nextStickIntent(false, { nearBottom: true, userMovedUp: true })).toBe(true);
+  });
+});

apps/desktop/src/lib/scrollController.ts

@@ -0,0 +1,62 @@
+// Pure, DOM-free scroll-decision logic for MessageList. Unit-tested so the
+// tricky math is verified without a browser (jsdom has no layout).
+
+export interface ScrollMetrics {
+  scrollTop: number;
+  scrollHeight: number;
+  clientHeight: number;
+}
+
+/** Distance from the bottom edge is within `threshold` px. */
+export function isNearBottom(m: ScrollMetrics, threshold: number): boolean {
+  return m.scrollHeight - (m.scrollTop + m.clientHeight) <= threshold;
+}
+
+/** Scroll offset is within `threshold` px of the top. */
+export function isNearTop(m: ScrollMetrics, threshold: number): boolean {
+  return m.scrollTop <= threshold;
+}
+
+export interface SavedPosition {
+  topmostIndex: number;
+  stickToBottom: boolean;
+}
+
+export interface Anchor {
+  index: number;
+  align: 'start' | 'end';
+}
+
+/**
+ * Where a freshly-opened chat should start.
+ * - default / "left at bottom" → last row, aligned to the viewport bottom.
+ * - "left scrolled up" → the saved top-most row, aligned to the viewport top
+ *   (clamped in case the cached row count shrank).
+ */
+export function resolveInitialAnchor(saved: SavedPosition | null, rowCount: number): Anchor {
+  if (rowCount <= 0) return { index: 0, align: 'end' };
+  if (saved && !saved.stickToBottom) {
+    const index = Math.max(0, Math.min(saved.topmostIndex, rowCount - 1));
+    return { index, align: 'start' };
+  }
+  return { index: rowCount - 1, align: 'end' };
+}
+
+/**
+ * The next stick-to-bottom intent given the current intent and the latest
+ * scroll signal. Intent only flips on a *definitive* signal:
+ * - reaching the bottom turns it ON,
+ * - a genuine user move-up turns it OFF.
+ * A neutral scroll — e.g. a measurement reflow that grows the content while
+ * rows settle — leaves the intent unchanged. This is the core fix for the
+ * chat-switch bug: a reflow must never be mistaken for the user scrolling up
+ * and so must never silently unstick the list.
+ */
+export function nextStickIntent(
+  prev: boolean,
+  signal: { nearBottom: boolean; userMovedUp: boolean },
+): boolean {
+  if (signal.nearBottom) return true;
+  if (signal.userMovedUp) return false;
+  return prev;
+}

apps/desktop/src/lib/useMessageReactions.ts

@@ -19,6 +19,10 @@ export interface UseMessageReactionsResult {
   byMessage: Map<string, AggregatedReaction[]>;
   toggle: (messageId: string, emoji: string) => Promise<void>;
   voteExclusive: (messageId: string, emoji: string, exclusiveEmojis: string[]) => Promise<void>;
+  // True once the reactions for the current message-id set have been fetched
+  // (or there are no messages). Drives MessageList's deferred reveal so the
+  // chat opens already showing reaction chips — no post-paint height jump.
+  ready: boolean;
 }
 
 // Batch-fetches reactions for the given message ids + subscribes to the
@@ -29,10 +33,12 @@ export function useMessageReactions(
 ): UseMessageReactionsResult {
   const idsKey = useMemo(() => messageIds.join(','), [messageIds]);
   const [rows, setRows] = useState<MessageReaction[]>([]);
+  const [readyKey, setReadyKey] = useState<string | null>(null);
 
   const refresh = useCallback(async () => {
     if (messageIds.length === 0) {
       setRows([]);
+      setReadyKey(idsKey);
       return;
     }
     try {
@@ -40,6 +46,8 @@ export function useMessageReactions(
       setRows(data);
     } catch (err: unknown) {
       console.error('listReactionsForMessages failed', err);
+    } finally {
+      setReadyKey(idsKey);
     }
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [idsKey]);
@@ -129,5 +137,7 @@ export function useMessageReactions(
     [byMessage, myId, refresh],
   );
 
-  return { byMessage, toggle, voteExclusive };
+  const ready = readyKey === idsKey;
+
+  return { byMessage, toggle, voteExclusive, ready };
 }

apps/desktop/src/pages/ConversationPage.tsx

@@ -3,7 +3,7 @@ import { extractErrorCode } from '@chat-app/shared/i18n';
 import { lazy, Suspense, useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useParams } from 'react-router-dom';
-import { Virtuoso, type VirtuosoHandle, type IndexLocationWithAlign } from 'react-virtuoso';
+import { MessageList, type MessageListHandle } from '../components/MessageList';
 
 import { ComposerActionsMenu } from '../components/ComposerActionsMenu';
 import { ConversationHeader } from '../components/ConversationHeader';
@@ -54,6 +54,7 @@ import {
   createWatchTogetherPayload,
   createGamePayload,
 } from '../lib/conversationFeatures';
+import { resolveInitialAnchor } from '../lib/scrollController';
 const WhiteboardModal = lazy(() =>
   import('../components/WhiteboardModal').then((m) => ({ default: m.WhiteboardModal })),
 );
@@ -84,7 +85,7 @@ import { clearDraft, getDraftSync, setDraft } from '../lib/composerDraftStore';
 // pending bubbles and the "load older" tile inside the same Virtuoso
 // instance means scroll-to-bottom / followOutput stay coherent across both
 // (we don't need a sibling scroll container for pending items).
-type VirtuosoRow =
+export type VirtuosoRow =
   | { kind: 'loader'; key: string }
   | { kind: 'message'; key: string; message: DecryptedMessage; idx: number }
   | { kind: 'pending'; key: string; item: OutboxItem };
@@ -145,6 +146,17 @@ export function ConversationPage() {
     voteExclusive: votePoll,
   } = useMessageReactions(messageIds, session?.user.id);
 
+  // Reveal gate for MessageList: as soon as messages exist (cache hit = first
+  // render, so no spinner and no wait), let the list reveal. We deliberately do
+  // NOT gate on reactions readiness: on a cache-hit chat switch the messages are
+  // already present, and gating on the async reactions fetch held the list at
+  // opacity:0 for up to 300ms and then "popped" it in — that was the residual
+  // chat-switch flicker. Reaction chips stream in a beat later; because the list
+  // is pinned to the bottom, their height growth re-pins with no visible jump.
+  // MessageList still defers its own reveal a few frames until the row-height
+  // measurement settles, so the list still appears already at the final bottom.
+  const listReady = !loading && messages.length > 0;
+
   const myId = session?.user.id;
 
   const ownMessageIds = useMemo(
@@ -303,7 +315,7 @@ export function ConversationPage() {
     },
     [send],
   );
-  const virtuosoRef = useRef<VirtuosoHandle>(null);
+  const listRef = useRef<MessageListHandle>(null);
   const topmostIndexRef = useRef<number>(0);
   const fileInputRef = useRef<HTMLInputElement>(null);
   const composerRef = useRef<HTMLTextAreaElement>(null);
@@ -471,30 +483,14 @@ export function ConversationPage() {
   // previous visit to this chat AND the user wasn't sticking to the
   // bottom, restore the saved row index (clamped to the current row
   // count in case the cache was trimmed).
-  const initialTopMostIndex = useMemo<number | IndexLocationWithAlign>(() => {
-    const saved = savedPositionRef.current;
-    if (saved && !saved.stickToBottom) {
-      // Restore the row the user was reading, pinned to the TOP of the
-      // viewport — that's the anchor the index was captured at
-      // (handleRangeChanged stores range.startIndex).
-      const idx = Math.max(0, Math.min(saved.topmostIndex, virtuosoRows.length - 1));
-      return { index: idx, align: 'start' };
-    }
-    // Bottom case (the common one): anchor the LAST row to the END (bottom)
-    // edge of the viewport. This is the fix for the "jumps once on chat
-    // switch" bug: a plain numeric index aligns the row to the TOP, so
-    // react-virtuoso paints with estimated row heights, then measures the
-    // real (taller) heights of the dynamic bubbles (avatars, attachments,
-    // multi-line text, reactions) and corrects scrollTop — a visible jump on
-    // every mount. `align: 'end'` pins the bottom edge instead, so the
-    // post-measurement height growth happens above the fold and the viewport
-    // stays put. This is react-virtuoso's canonical "start at the bottom" form.
-    return { index: 'LAST', align: 'end' };
-    // virtuosoRows.length flipping 0 -> >0 is the intentional trigger so a
-    // freshly-loaded chat anchors on first paint; we deliberately don't
-    // re-derive on every row append — Virtuoso owns scroll position after.
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [virtuosoRows.length > 0]);
+  // Reuses the unit-tested resolveInitialAnchor so the "where do I open" rule
+  // lives in one tested place. MessageList only reads this at reveal time (when
+  // rows are loaded), so depending on the row count clamps a stale saved index
+  // correctly without freezing a mount-time count of 0.
+  const initialAnchor = useMemo<{ type: 'bottom' } | { type: 'row'; index: number }>(() => {
+    const anchor = resolveInitialAnchor(savedPositionRef.current, virtuosoRows.length);
+    return anchor.align === 'end' ? { type: 'bottom' } : { type: 'row', index: anchor.index };
+  }, [virtuosoRows.length]);
 
   const jumpToMessage = useCallback(
     (targetId: string) => {
@@ -521,11 +517,7 @@ export function ConversationPage() {
       // resolve the target row. Without this, the scroll either no-ops or
       // lands on a stale row.
       requestAnimationFrame(() => {
-        virtuosoRef.current?.scrollToIndex({
-          index: rowIndex,
-          align: 'center',
-          behavior: 'smooth',
-        });
+        listRef.current?.scrollToRow(rowIndex, 'center', 'smooth');
       });
       setHighlightedId(targetId);
       window.setTimeout(
@@ -721,23 +713,26 @@ export function ConversationPage() {
   const handleRangeChanged = useCallback(
     (range: { startIndex: number; endIndex: number }) => {
       topmostIndexRef.current = range.startIndex;
-      if (id) {
+      if (!id) return;
+      if (stickToBottom) {
+        // Pinned to the bottom: the topmost-visible row drifts as the
+        // virtualizer mounts/unmounts rows. Persisting it would later reopen the
+        // chat at that arbitrary row (the second writer behind the scrollTop=0
+        // bug). Keep the last real reading position and only refresh the flag.
         const prev = scrollPositions.get(id);
         scrollPositions.set(id, {
-          topmostIndex: range.startIndex,
-          stickToBottom: prev?.stickToBottom ?? true,
+          topmostIndex: prev?.topmostIndex ?? range.startIndex,
+          stickToBottom: true,
         });
+      } else {
+        scrollPositions.set(id, { topmostIndex: range.startIndex, stickToBottom: false });
       }
     },
-    [id],
+    [id, stickToBottom],
   );
 
   const jumpToBottom = useCallback(() => {
-    virtuosoRef.current?.scrollToIndex({
-      index: 'LAST',
-      align: 'end',
-      behavior: 'smooth',
-    });
+    listRef.current?.scrollToBottom('smooth');
     setStickToBottom(true);
     setNewMessagesWhileAway(0);
   }, []);
@@ -757,11 +752,7 @@ export function ConversationPage() {
   const lastPendingCountRef = useRef(pending.length);
   useEffect(() => {
     if (pending.length > lastPendingCountRef.current) {
-      virtuosoRef.current?.scrollToIndex({
-        index: 'LAST',
-        align: 'end',
-        behavior: 'auto',
-      });
+      listRef.current?.scrollToBottom('auto');
     }
     lastPendingCountRef.current = pending.length;
   }, [pending.length]);
@@ -776,11 +767,7 @@ export function ConversationPage() {
   // targets the correct bottom edge.
   const snapToBottom = useCallback(() => {
     window.requestAnimationFrame(() => {
-      virtuosoRef.current?.scrollToIndex({
-        index: 'LAST',
-        align: 'end',
-        behavior: 'auto',
-      });
+      listRef.current?.scrollToBottom('auto');
     });
   }, []);
 
@@ -1065,49 +1052,24 @@ export function ConversationPage() {
             />
           </div>
         ) : (
-          <Virtuoso
-            ref={virtuosoRef}
-            className="flex-1"
-            style={{ height: '100%' }}
-            data={virtuosoRows}
-            computeItemKey={(_idx, row) => row.key}
-            // Initial position: either restored from per-conv memory, or
-            // pinned to the bottom for fresh entry. Virtuoso applies this
-            // synchronously before its first paint so the user doesn't see
-            // a "loaded at top, then jumped" flicker (matches the layout-
-            // effect behavior we used in the non-virtualized version).
-            initialTopMostItemIndex={initialTopMostIndex}
-            // followOutput auto-scrolls only when the user was already at
-            // the bottom; returning `false` from the callback when they're
-            // scrolled up preserves their reading position when realtime
-            // messages arrive (critical UX: do NOT jerk the user).
-            //
-            // We deliberately use 'auto' (instant) rather than 'smooth':
-            // with a smooth scroll animation, atBottomStateChange fires
-            // `false` mid-animation (scrollTop is briefly above the new
-            // bottom) and then `true` after settle — that flips
-            // stickToBottom twice, flashing the "Zum neuesten" pill and
-            // re-rendering the whole list. Instant scroll has zero
-            // mid-animation state so the cascade never happens.
-            followOutput={(isAtBottom) => (isAtBottom ? 'auto' : false)}
-            atBottomStateChange={handleAtBottomStateChange}
-            // 250 px tolerance — large enough that appending a tall row
-            // (image, voice note, grouped attachments) doesn't push the
-            // user out of the at-bottom zone. The previous 80 px flipped
-            // stickToBottom on nearly every typical message arrival.
+          <MessageList
+            ref={listRef}
+            rows={virtuosoRows}
+            // Deferred reveal: the list stays hidden until messages + reactions
+            // + the unread divider are loaded, then anchors and reveals — so the
+            // post-paint height cascade is never visible (no chat-switch flicker).
+            ready={listReady}
+            computeKey={(row) => row.key}
+            initialAnchor={initialAnchor}
+            // 250px at-bottom tolerance — a tall appended row (image, voice note,
+            // grouped attachments) shouldn't push the user out of the at-bottom zone.
             atBottomThreshold={250}
-            rangeChanged={handleRangeChanged}
-            startReached={handleStartReached}
-            // Render rows just outside the viewport so fast scrolling
-            // doesn't briefly flash empty space.
-            increaseViewportBy={400}
-            // Visual breathing space below the last message so a bubble
-            // bottom doesn't sit flush against the composer top — matches
-            // Discord's chat-pane bottom padding.
-            components={{
-              Footer: () => <div style={{ height: '12px' }} />,
-            }}
-            itemContent={(_index, row) => {
+            onReachTop={handleStartReached}
+            onAtBottomChange={handleAtBottomStateChange}
+            onTopRowChange={(topIndex) =>
+              handleRangeChanged({ startIndex: topIndex, endIndex: topIndex })
+            }
+            renderRow={(_index, row) => {
               if (row.kind === 'loader') {
                 return (
                   <div className="flex items-center justify-center py-2 text-xs text-fg-muted">

docs/superpowers/plans/2026-06-02-message-list-scroll-rewrite.md

@@ -0,0 +1,673 @@
+# Message-List / Scroll Rewrite — Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Replace the `react-virtuoso` message list with a TanStack-Virtual list that opens/switches chats flicker-free (Discord-like), preserving every existing behavior.
+
+**Architecture:** Pure scroll-decision logic (`scrollController.ts`, unit-tested) + an isolated virtualization component (`MessageList.tsx`, TanStack Virtual, deferred reveal) + `ConversationPage` wiring. The flicker is killed by keeping the list hidden until messages+reactions+divider are stable, then anchoring before paint.
+
+**Tech Stack:** React 18, TypeScript, `@tanstack/react-virtual` (new), vitest, electron-vite.
+
+Spec: `docs/superpowers/specs/2026-06-02-message-list-scroll-rewrite-design.md`
+
+---
+
+## File Structure
+
+- Create: `apps/desktop/src/lib/scrollController.ts` — pure scroll math (no DOM/React).
+- Create: `apps/desktop/src/lib/scrollController.test.ts` — vitest unit tests.
+- Create: `apps/desktop/src/components/MessageList.tsx` — TanStack virtual list + reveal/stick/load-older. Exports `MessageList`, `MessageListHandle`, `VirtuosoRow` is imported from ConversationPage's shared type (moved in Task 5).
+- Modify: `apps/desktop/src/lib/useMessageReactions.ts` — add `ready` flag for the reveal gate.
+- Modify: `apps/desktop/src/pages/ConversationPage.tsx` — export the row type, swap `<Virtuoso>` for `<MessageList>`, drive the handle, pass `ready`.
+- Modify: `apps/desktop/package.json` — add `@tanstack/react-virtual`; remove `react-virtuoso` (Task 8).
+
+---
+
+## Task 1: Add the TanStack Virtual dependency
+
+**Files:**
+- Modify: `apps/desktop/package.json`
+
+- [ ] **Step 1: Install**
+
+Run (from repo root `chat-app/`):
+```bash
+pnpm --filter @chat-app/desktop add @tanstack/react-virtual@^3.10.0
+```
+Expected: adds `@tanstack/react-virtual` to `apps/desktop/package.json` dependencies; lockfile updated.
+
+- [ ] **Step 2: Verify it resolves**
+
+Run: `pnpm --filter @chat-app/desktop exec node -e "require.resolve('@tanstack/react-virtual'); console.log('ok')"`
+Expected: `ok`
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add apps/desktop/package.json pnpm-lock.yaml
+git commit -m "build(desktop): add @tanstack/react-virtual"
+```
+
+---
+
+## Task 2: Pure scroll-decision logic (TDD)
+
+**Files:**
+- Create: `apps/desktop/src/lib/scrollController.ts`
+- Test: `apps/desktop/src/lib/scrollController.test.ts`
+
+- [ ] **Step 1: Write the failing tests**
+
+```ts
+// apps/desktop/src/lib/scrollController.test.ts
+import { describe, expect, it } from 'vitest';
+import { isNearBottom, isNearTop, resolveInitialAnchor } from './scrollController';
+
+const m = (scrollTop: number, scrollHeight: number, clientHeight: number) => ({
+  scrollTop,
+  scrollHeight,
+  clientHeight,
+});
+
+describe('isNearBottom', () => {
+  it('true exactly at the bottom', () => {
+    expect(isNearBottom(m(900, 1000, 100), 64)).toBe(true);
+  });
+  it('true within threshold', () => {
+    expect(isNearBottom(m(860, 1000, 100), 64)).toBe(true);
+  });
+  it('false beyond threshold', () => {
+    expect(isNearBottom(m(800, 1000, 100), 64)).toBe(false);
+  });
+});
+
+describe('isNearTop', () => {
+  it('true at top', () => {
+    expect(isNearTop(m(0, 1000, 100), 64)).toBe(true);
+  });
+  it('false past threshold', () => {
+    expect(isNearTop(m(200, 1000, 100), 64)).toBe(false);
+  });
+});
+
+describe('resolveInitialAnchor', () => {
+  it('anchors to last row at end by default (no saved position)', () => {
+    expect(resolveInitialAnchor(null, 50)).toEqual({ index: 49, align: 'end' });
+  });
+  it('anchors to bottom when saved position stuck to bottom', () => {
+    expect(resolveInitialAnchor({ topmostIndex: 10, stickToBottom: true }, 50)).toEqual({
+      index: 49,
+      align: 'end',
+    });
+  });
+  it('restores the saved row at the top when scrolled up', () => {
+    expect(resolveInitialAnchor({ topmostIndex: 12, stickToBottom: false }, 50)).toEqual({
+      index: 12,
+      align: 'start',
+    });
+  });
+  it('clamps a stale saved index to the current row count', () => {
+    expect(resolveInitialAnchor({ topmostIndex: 999, stickToBottom: false }, 50)).toEqual({
+      index: 49,
+      align: 'start',
+    });
+  });
+  it('handles an empty list', () => {
+    expect(resolveInitialAnchor(null, 0)).toEqual({ index: 0, align: 'end' });
+  });
+});
+```
+
+- [ ] **Step 2: Run, verify FAIL**
+
+Run: `pnpm --filter @chat-app/desktop exec vitest run src/lib/scrollController.test.ts`
+Expected: FAIL — "Failed to resolve import './scrollController'".
+
+- [ ] **Step 3: Implement**
+
+```ts
+// apps/desktop/src/lib/scrollController.ts
+// Pure, DOM-free scroll-decision logic for MessageList. Unit-tested so the
+// tricky math is verified without a browser (jsdom has no layout).
+
+export interface ScrollMetrics {
+  scrollTop: number;
+  scrollHeight: number;
+  clientHeight: number;
+}
+
+/** Distance from the bottom edge is within `threshold` px. */
+export function isNearBottom(m: ScrollMetrics, threshold: number): boolean {
+  return m.scrollHeight - (m.scrollTop + m.clientHeight) <= threshold;
+}
+
+/** Scroll offset is within `threshold` px of the top. */
+export function isNearTop(m: ScrollMetrics, threshold: number): boolean {
+  return m.scrollTop <= threshold;
+}
+
+export interface SavedPosition {
+  topmostIndex: number;
+  stickToBottom: boolean;
+}
+
+export interface Anchor {
+  index: number;
+  align: 'start' | 'end';
+}
+
+/**
+ * Where a freshly-opened chat should start.
+ * - default / "left at bottom" → last row, aligned to the viewport bottom.
+ * - "left scrolled up" → the saved top-most row, aligned to the viewport top
+ *   (clamped in case the cached row count shrank).
+ */
+export function resolveInitialAnchor(saved: SavedPosition | null, rowCount: number): Anchor {
+  if (rowCount <= 0) return { index: 0, align: 'end' };
+  if (saved && !saved.stickToBottom) {
+    const index = Math.max(0, Math.min(saved.topmostIndex, rowCount - 1));
+    return { index, align: 'start' };
+  }
+  return { index: rowCount - 1, align: 'end' };
+}
+```
+
+- [ ] **Step 4: Run, verify PASS**
+
+Run: `pnpm --filter @chat-app/desktop exec vitest run src/lib/scrollController.test.ts`
+Expected: PASS (11 tests).
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add apps/desktop/src/lib/scrollController.ts apps/desktop/src/lib/scrollController.test.ts
+git commit -m "feat(desktop): pure scroll-decision logic for new message list"
+```
+
+---
+
+## Task 3: Reveal-gate flag on `useMessageReactions`
+
+**Files:**
+- Modify: `apps/desktop/src/lib/useMessageReactions.ts`
+
+Reactions are the main post-paint height changer. The list reveal waits on their first
+fetch, so add a `ready` flag that is true once reactions for the current message-id set
+have been fetched (or there are no messages).
+
+- [ ] **Step 1: Add `ready` to the result type + state**
+
+In `UseMessageReactionsResult` add:
+```ts
+  ready: boolean;
+```
+After `const [rows, setRows] = useState<MessageReaction[]>([]);` add:
+```ts
+  const [readyKey, setReadyKey] = useState<string | null>(null);
+```
+
+- [ ] **Step 2: Set the key after each fetch**
+
+Replace the `refresh` callback body so both branches stamp `readyKey`:
+```ts
+  const refresh = useCallback(async () => {
+    if (messageIds.length === 0) {
+      setRows([]);
+      setReadyKey(idsKey);
+      return;
+    }
+    try {
+      const data = await listReactionsForMessages(supabase, messageIds);
+      setRows(data);
+    } catch (err: unknown) {
+      console.error('listReactionsForMessages failed', err);
+    } finally {
+      setReadyKey(idsKey);
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [idsKey]);
+```
+
+- [ ] **Step 3: Derive + return `ready`**
+
+Before the `return`:
+```ts
+  const ready = readyKey === idsKey;
+```
+And add `ready` to the returned object:
+```ts
+  return { byMessage, toggle, voteExclusive, ready };
+```
+
+- [ ] **Step 4: Typecheck**
+
+Run: `pnpm --filter @chat-app/desktop typecheck`
+Expected: PASS (no output).
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add apps/desktop/src/lib/useMessageReactions.ts
+git commit -m "feat(desktop): expose reactions reveal-gate flag (ready)"
+```
+
+---
+
+## Task 4: Export the shared row type from ConversationPage
+
+**Files:**
+- Modify: `apps/desktop/src/pages/ConversationPage.tsx`
+
+`MessageList` needs the row union. Export it from ConversationPage (smallest change;
+the type already lives there).
+
+- [ ] **Step 1: Export the type**
+
+Change the `type VirtuosoRow = …` declaration (near the top of the file) to:
+```ts
+export type VirtuosoRow =
+  | { kind: 'loader'; key: string }
+  | { kind: 'message'; key: string; message: DecryptedMessage; idx: number }
+  | { kind: 'pending'; key: string; item: OutboxItem };
+```
+
+- [ ] **Step 2: Typecheck**
+
+Run: `pnpm --filter @chat-app/desktop typecheck`
+Expected: PASS.
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add apps/desktop/src/pages/ConversationPage.tsx
+git commit -m "refactor(desktop): export VirtuosoRow type for MessageList"
+```
+
+---
+
+## Task 5: The `MessageList` component
+
+**Files:**
+- Create: `apps/desktop/src/components/MessageList.tsx`
+
+This is the integration unit. It is verified by typecheck here and **visually in dev**
+in Task 7 (jsdom can't layout-test it). The TanStack specifics (scrollToIndex timing,
+prepend offset) are the parts to refine during dev iteration.
+
+- [ ] **Step 1: Implement**
+
+```tsx
+// apps/desktop/src/components/MessageList.tsx
+import { useVirtualizer } from '@tanstack/react-virtual';
+import {
+  forwardRef,
+  useCallback as _unused, // placeholder removed below
+} from 'react';
+```
+> NOTE for the implementer: write the file with the imports below (the line above is
+> illustrative only — do not keep it). Full file:
+
+```tsx
+import { useVirtualizer } from '@tanstack/react-virtual';
+import {
+  forwardRef,
+  useCallback,
+  useImperativeHandle,
+  useLayoutEffect,
+  useRef,
+  useState,
+  type ReactNode,
+} from 'react';
+
+import { isNearBottom, isNearTop, resolveInitialAnchor, type Anchor } from '../lib/scrollController';
+import type { VirtuosoRow } from '../pages/ConversationPage';
+
+export interface MessageListHandle {
+  scrollToBottom(behavior?: ScrollBehavior): void;
+  scrollToRow(index: number, align?: 'center' | 'end', behavior?: ScrollBehavior): void;
+}
+
+export interface MessageListProps {
+  rows: VirtuosoRow[];
+  renderRow: (index: number, row: VirtuosoRow) => ReactNode;
+  computeKey: (row: VirtuosoRow) => string;
+  initialAnchor: { type: 'bottom' } | { type: 'row'; index: number };
+  /** Reveal gate — list stays hidden behind a spinner until true (no flicker). */
+  ready: boolean;
+  estimateRowHeight?: number;
+  atBottomThreshold?: number;
+  onReachTop?: () => void;
+  onAtBottomChange?: (atBottom: boolean) => void;
+  onTopRowChange?: (topIndex: number) => void;
+}
+
+export const MessageList = forwardRef<MessageListHandle, MessageListProps>(function MessageList(
+  {
+    rows,
+    renderRow,
+    computeKey,
+    initialAnchor,
+    ready,
+    estimateRowHeight = 64,
+    atBottomThreshold = 64,
+    onReachTop,
+    onAtBottomChange,
+    onTopRowChange,
+  },
+  ref,
+) {
+  const scrollElRef = useRef<HTMLDivElement>(null);
+  const [revealed, setRevealed] = useState(false);
+  const atBottomRef = useRef(true);
+  // Load-older preservation: remember scrollHeight + first key across renders.
+  const prevFirstKeyRef = useRef<string | null>(null);
+  const prevScrollHeightRef = useRef(0);
+
+  const virtualizer = useVirtualizer({
+    count: rows.length,
+    getScrollElement: () => scrollElRef.current,
+    estimateSize: () => estimateRowHeight,
+    overscan: 8,
+    getItemKey: (index) => computeKey(rows[index]!),
+  });
+
+  const metrics = () => {
+    const el = scrollElRef.current;
+    return el
+      ? { scrollTop: el.scrollTop, scrollHeight: el.scrollHeight, clientHeight: el.clientHeight }
+      : { scrollTop: 0, scrollHeight: 0, clientHeight: 0 };
+  };
+
+  const applyAnchor = useCallback(
+    (anchor: Anchor) => {
+      virtualizer.scrollToIndex(anchor.index, { align: anchor.align });
+      // Re-apply on the next frame: dynamic measurement settles after the first
+      // paint, so a single scrollToIndex can land a few px off. The list is still
+      // hidden here, so this correction is never visible.
+      requestAnimationFrame(() => virtualizer.scrollToIndex(anchor.index, { align: anchor.align }));
+    },
+    [virtualizer],
+  );
+
+  // Deferred reveal: when ready, anchor (before paint) then reveal.
+  useLayoutEffect(() => {
+    if (!ready || revealed || rows.length === 0) return;
+    const anchor: Anchor =
+      initialAnchor.type === 'bottom'
+        ? { index: rows.length - 1, align: 'end' }
+        : { index: Math.max(0, Math.min(initialAnchor.index, rows.length - 1)), align: 'start' };
+    applyAnchor(anchor);
+    atBottomRef.current = initialAnchor.type === 'bottom';
+    onAtBottomChange?.(atBottomRef.current);
+    requestAnimationFrame(() => setRevealed(true));
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [ready, rows.length]);
+
+  // Stick-to-bottom: when content grows and we were at the bottom, re-pin.
+  useLayoutEffect(() => {
+    if (!revealed) return;
+    if (atBottomRef.current) {
+      virtualizer.scrollToIndex(rows.length - 1, { align: 'end' });
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [rows.length, virtualizer.getTotalSize()]);
+
+  // Load-older preservation: if rows were prepended (first key changed and count
+  // grew), restore scrollTop by the height delta so the viewport stays put.
+  useLayoutEffect(() => {
+    const firstKey = rows.length > 0 ? computeKey(rows[0]!) : null;
+    const el = scrollElRef.current;
+    if (el && revealed && prevFirstKeyRef.current && firstKey !== prevFirstKeyRef.current) {
+      const delta = el.scrollHeight - prevScrollHeightRef.current;
+      if (delta > 0 && el.scrollTop < atBottomThreshold) {
+        el.scrollTop += delta;
+      }
+    }
+    prevFirstKeyRef.current = firstKey;
+    prevScrollHeightRef.current = el?.scrollHeight ?? 0;
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [rows]);
+
+  const handleScroll = useCallback(() => {
+    const m = metrics();
+    const atBottom = isNearBottom(m, atBottomThreshold);
+    if (atBottom !== atBottomRef.current) {
+      atBottomRef.current = atBottom;
+      onAtBottomChange?.(atBottom);
+    }
+    if (isNearTop(m, atBottomThreshold * 4)) onReachTop?.();
+    const first = virtualizer.getVirtualItems()[0];
+    if (first) onTopRowChange?.(first.index);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [atBottomThreshold, onAtBottomChange, onReachTop, onTopRowChange, virtualizer]);
+
+  useImperativeHandle(
+    ref,
+    () => ({
+      scrollToBottom: () => {
+        atBottomRef.current = true;
+        virtualizer.scrollToIndex(rows.length - 1, { align: 'end' });
+      },
+      scrollToRow: (index, align = 'center') => {
+        virtualizer.scrollToIndex(index, { align });
+      },
+    }),
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+    [virtualizer, rows.length],
+  );
+
+  const items = virtualizer.getVirtualItems();
+
+  return (
+    <div
+      ref={scrollElRef}
+      onScroll={handleScroll}
+      className="h-full overflow-y-auto"
+      style={{ opacity: revealed ? 1 : 0, position: 'relative' }}
+    >
+      <div style={{ height: virtualizer.getTotalSize(), position: 'relative', width: '100%' }}>
+        {items.map((vi) => (
+          <div
+            key={vi.key}
+            data-index={vi.index}
+            ref={virtualizer.measureElement}
+            style={{ position: 'absolute', top: 0, left: 0, width: '100%', transform: `translateY(${vi.start}px)` }}
+          >
+            {renderRow(vi.index, rows[vi.index]!)}
+          </div>
+        ))}
+      </div>
+      {/* 12px bottom breathing space (matches the old Footer). */}
+      <div style={{ height: 12 }} />
+    </div>
+  );
+});
+```
+> Implementer note: delete the illustrative first `import` snippet; keep only the full
+> file. The `requestAnimationFrame` timing in `applyAnchor`/reveal is the most likely
+> spot to refine during dev (Task 7).
+
+- [ ] **Step 2: Typecheck**
+
+Run: `pnpm --filter @chat-app/desktop typecheck`
+Expected: PASS.
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add apps/desktop/src/components/MessageList.tsx
+git commit -m "feat(desktop): TanStack-Virtual MessageList with deferred reveal"
+```
+
+---
+
+## Task 6: Wire `MessageList` into `ConversationPage`
+
+**Files:**
+- Modify: `apps/desktop/src/pages/ConversationPage.tsx`
+
+- [ ] **Step 1: Imports + reveal gate**
+
+Replace the `react-virtuoso` import with:
+```ts
+import { MessageList, type MessageListHandle } from '../components/MessageList';
+```
+Capture the reactions `ready` flag — change the `useMessageReactions` destructure to also pull `ready`:
+```ts
+  const {
+    byMessage: reactionsByMessage,
+    toggle: toggleReaction,
+    voteExclusive: votePoll,
+    ready: reactionsReady,
+  } = useMessageReactions(messageIds, session?.user.id);
+```
+Add a reveal gate with a 300ms max-timeout fallback (so empty/slow reactions never hang):
+```ts
+  const [revealTimedOut, setRevealTimedOut] = useState(false);
+  useEffect(() => {
+    if (!id || loading || messages.length === 0) return;
+    const t = window.setTimeout(() => setRevealTimedOut(true), 300);
+    return () => window.clearTimeout(t);
+  }, [id, loading, messages.length]);
+  const listReady = !loading && messages.length > 0 && (reactionsReady || revealTimedOut);
+```
+
+- [ ] **Step 2: Replace the `virtuosoRef` type + handle**
+
+Change:
+```ts
+  const virtuosoRef = useRef<VirtuosoHandle>(null);
+```
+to:
+```ts
+  const listRef = useRef<MessageListHandle>(null);
+```
+Replace every `virtuosoRef.current?.scrollToIndex({ index: 'LAST', align: 'end', behavior })`
+call (in `jumpToBottom`, the pending-snap effect, `snapToBottom`) with:
+```ts
+  listRef.current?.scrollToBottom('auto');
+```
+Replace the `jumpToMessage` scroll (`virtuosoRef.current?.scrollToIndex({ index: rowIndex, align: 'center', behavior: 'smooth' })`) with:
+```ts
+  listRef.current?.scrollToRow(rowIndex, 'center', 'smooth');
+```
+
+- [ ] **Step 3: Compute `initialAnchor`**
+
+Replace the `initialTopMostIndex` `useMemo` (the `IndexLocationWithAlign` one from the
+earlier hotfix) with:
+```ts
+  const initialAnchor = useMemo<{ type: 'bottom' } | { type: 'row'; index: number }>(() => {
+    const saved = savedPositionRef.current;
+    if (saved && !saved.stickToBottom) return { type: 'row', index: saved.topmostIndex };
+    return { type: 'bottom' };
+  }, []);
+```
+Remove the now-unused `IndexLocationWithAlign` import.
+
+- [ ] **Step 4: Swap the JSX**
+
+Replace the entire `<Virtuoso … />` element with:
+```tsx
+          <MessageList
+            ref={listRef}
+            rows={virtuosoRows}
+            ready={listReady}
+            computeKey={(row) => row.key}
+            initialAnchor={initialAnchor}
+            atBottomThreshold={250}
+            onReachTop={handleStartReached}
+            onAtBottomChange={handleAtBottomStateChange}
+            onTopRowChange={(topIndex) => handleRangeChanged({ startIndex: topIndex, endIndex: topIndex })}
+            renderRow={(_index, row) => {
+              // ...exact same body the old `itemContent` had (loader / pending /
+              // message branches) — move it verbatim from the deleted <Virtuoso>.
+              return renderConversationRow(row);
+            }}
+          />
+```
+Move the old `itemContent` body into a local `renderConversationRow(row)` helper (or inline it) so the message/loader/pending branches are unchanged. `handleRangeChanged` already accepts `{ startIndex, endIndex }`.
+
+- [ ] **Step 5: Typecheck + unit tests**
+
+Run: `pnpm --filter @chat-app/desktop typecheck && pnpm --filter @chat-app/desktop test`
+Expected: PASS.
+
+- [ ] **Step 6: Commit**
+
+```bash
+git add apps/desktop/src/pages/ConversationPage.tsx
+git commit -m "feat(desktop): use MessageList in ConversationPage (replace react-virtuoso)"
+```
+
+---
+
+## Task 7: Dev verification (with the user) — iterate until smooth
+
+**Files:** none (runtime verification)
+
+- [ ] **Step 1: Run the dev build**
+
+User runs (in `chat-app/`): `pnpm desktop:dev`
+
+- [ ] **Step 2: Verify behaviors live**
+
+Switch between several chats repeatedly and confirm, using the `SCROLL_DEBUG` console
+output where helpful:
+- No jump and no multi-flicker on chat switch (opens cleanly at the bottom / saved row).
+- New message while at bottom auto-scrolls; while scrolled up shows the pill.
+- Unread divider present without a later shift.
+- Scroll to top loads older without the viewport jumping.
+- Jump-to-message (reply tap / pinned / search) scrolls to the target.
+- Sent/pending message snaps to bottom.
+
+- [ ] **Step 3: Refine**
+
+If any behavior is off, adjust `MessageList.tsx` (most likely the `applyAnchor`/reveal
+`requestAnimationFrame` timing or the stick-to-bottom effect) and re-verify. Commit each
+refinement:
+```bash
+git commit -am "fix(desktop): refine MessageList <specific behavior>"
+```
+
+---
+
+## Task 8: Cleanup + release 0.21.6
+
+**Files:**
+- Modify: `apps/desktop/src/pages/ConversationPage.tsx` (remove instrumentation)
+- Modify: `apps/desktop/package.json` (remove `react-virtuoso`)
+
+- [ ] **Step 1: Remove the `SCROLL_DEBUG` instrumentation**
+
+Delete the `SCROLL_DEBUG`/`dbgNow`/`dbgLog` block, the render-logger `useEffect`, and the
+`dbgLog(...)` calls inside `handleRangeChanged` / `handleAtBottomStateChange`.
+
+- [ ] **Step 2: Remove the old dependency**
+
+Run: `pnpm --filter @chat-app/desktop remove react-virtuoso`
+Then confirm no references remain:
+Run: `grep -rn "react-virtuoso\|Virtuoso\b" apps/desktop/src || echo "clean"`
+Expected: `clean`.
+
+- [ ] **Step 3: Typecheck + tests + commit**
+
+Run: `pnpm --filter @chat-app/desktop typecheck && pnpm --filter @chat-app/desktop test`
+Expected: PASS.
+```bash
+git add -A
+git commit -m "chore(desktop): drop react-virtuoso + scroll debug instrumentation"
+```
+
+- [ ] **Step 4: Release**
+
+Run (from `chat-app/`, tree clean): `node scripts/release.mjs 0.21.6 "- Nachrichtenliste komplett überarbeitet: Chat-Wechsel öffnet jetzt ruckel- und flackerfrei direkt unten\n- Älteren Verlauf laden springt nicht mehr"`
+Then verify `latest.yml` shows 0.21.6 on `update.netralax.de` **and** `update.netralax.cloud`.
+
+---
+
+## Self-Review
+
+- **Spec coverage:** deferred reveal (Tasks 3,5,6) ✓; TanStack virtualization (Tasks 1,5) ✓; isolation into MessageList + scrollController (Tasks 2,5) ✓; stick-to-bottom (Task 5) ✓; load-older preservation (Task 5) ✓; preserved behaviors incl. jump-to-message/pill/divider/pending (Task 6) ✓; pure-logic unit tests (Task 2) ✓; dev verification (Task 7) ✓; cleanup + release (Task 8) ✓.
+- **Placeholders:** the only prose-only steps are the deliberately runtime Task 7 (no code possible) and the "move itemContent verbatim" in Task 6 Step 4 (the body is large and unchanged — copying it verbatim, not rewriting). The illustrative throwaway import in Task 5 Step 1 is explicitly flagged for deletion.
+- **Type consistency:** `MessageListHandle.scrollToBottom/scrollToRow`, `VirtuosoRow`, `Anchor`, `ScrollMetrics`, `resolveInitialAnchor` signatures are consistent across Tasks 2/5/6. `ready` flag added in Task 3 is consumed in Task 6.

docs/superpowers/specs/2026-06-02-message-list-scroll-rewrite-design.md

@@ -0,0 +1,184 @@
+# Message-List / Scroll Rewrite — Design
+
+Date: 2026-06-02
+Status: Approved (brainstorming) — pending spec review → implementation plan
+Scope: Desktop app only (`apps/desktop`). Mobile is out of scope.
+
+## 1. Problem & Root Cause
+
+Switching conversations causes a visible jump and then a multi-flicker. Root cause
+(established via systematic debugging, not guessing):
+
+- The message list is **virtualized** (`react-virtuoso`). Virtualization paints rows
+  with *estimated* heights, then measures real heights and corrects `scrollTop`.
+- On chat open, several async sources change **row heights after the first paint**:
+  message **reactions** (`useMessageReactions`), the **unread divider**
+  (`firstUnreadId`), delivery/read **receipts**, and the **two-phase message load**
+  (in-memory cache render → server `refresh()` replaces the array).
+- Each post-paint height change makes the virtualizer re-measure and re-anchor →
+  the viewport visibly moves several times = "flickert paar mal".
+
+A first targeted fix (`initialTopMostItemIndex: { index: 'LAST', align: 'end' }`)
+addressed only the *initial* anchor, not the post-paint cascade — so the flicker
+remained/worsened. Conclusion: re-architect the scroll system.
+
+## 2. Goals / Success Criteria
+
+1. Opening or switching a chat lands cleanly at the bottom (or the saved scrolled-up
+   row) with **no visible jump or flicker**.
+2. Discord-like live behavior: auto-scroll on new message when at bottom; "X new
+   messages" pill when scrolled up; unread divider; load-older without the viewport
+   jumping; jump-to-message / search / pin scroll.
+3. Scales to **large conversations** (thousands of messages, deep back-scroll) —
+   virtualization stays.
+4. No regression of the existing features that live in `ConversationPage`.
+
+## 3. Decision
+
+Build on **`@tanstack/react-virtual`** (MIT, free) as the virtualization primitive,
+and kill the flicker at its root with a **deferred-reveal** strategy: never show the
+list while its row heights are still settling.
+
+Rejected alternatives: keeping `react-virtuoso` (we are fighting it); the commercial
+`@virtuoso.dev/message-list` (license cost); dropping virtualization entirely
+(large chats would render thousands of DOM nodes).
+
+## 4. Architecture (isolation)
+
+The scroll/virtualization logic moves out of the ~2000-line `ConversationPage` into
+two focused, independently-testable units:
+
+- **`apps/desktop/src/components/MessageList.tsx`** — owns the scroll container,
+  the TanStack virtualizer, dynamic measurement, deferred reveal, stick-to-bottom,
+  and load-older position preservation. Receives rows + a render function; emits
+  scroll events + exposes an imperative handle. Knows nothing about messages,
+  reactions, drafts, calls, etc.
+- **`apps/desktop/src/lib/scrollController.ts`** — the **pure**, DOM-free decision
+  logic (anchor computation, "should auto-scroll to bottom?", load-older index/offset
+  math, at-bottom threshold). Unit-tested with vitest.
+- **`ConversationPage`** keeps all feature state and rendering; it builds the same
+  `VirtuosoRow[]` discriminated union (`loader | message | pending`), passes them +
+  the existing per-row render (`itemContent`) into `<MessageList>`, and drives the
+  imperative handle for jump-to-message/search.
+
+Boundary contract: *in* = rows + renderRow; *out* = scroll events + an imperative
+handle. The internals of `MessageList` can change without touching `ConversationPage`.
+
+## 5. No-Flicker Core
+
+### 5.1 Deferred reveal
+`MessageList` is always mounted (so TanStack can measure the initial window), but
+rendered **visually hidden** (`opacity: 0`, pointer-events none) behind a spinner
+until `ready` is true. When `ready` flips true, in a `useLayoutEffect` (before the
+browser paints) it scrolls to `initialAnchor` (bottom, or the saved row), then
+reveals (`opacity: 1`) and removes the spinner. The user sees: brief spinner →
+final, correctly-anchored list. The height-changing cascade happens **while hidden**.
+
+`ready` (owned by `ConversationPage`, passed in) is defined as:
+- messages loaded (`!loading && rows.length > 0`), **AND**
+- the initial **reactions** fetch for the current message-id set has completed
+  (requires adding a `ready`/`loaded` flag to `useMessageReactions`), **AND**
+- a hard **max-timeout of ~300 ms** fallback so a slow/empty reactions fetch never
+  hangs the reveal.
+
+The unread divider is computed synchronously in an effect right after messages load,
+i.e. before reactions resolve — so it is present before reveal. Delivery/read receipts
+render as inline ticks (no meaningful height change) and are intentionally **not**
+gated.
+
+### 5.2 Stick-to-bottom
+A `ResizeObserver` on the inner content element: while the user is at the bottom
+(within `atBottomThreshold`, default 64px), any content-size growth re-pins the view
+to the bottom in a layout effect (before paint) — so a live incoming message/reaction
+never leaves the newest message half-scrolled.
+
+### 5.3 Dynamic measurement
+TanStack `measureElement` (ResizeObserver per rendered row) handles variable bubble
+heights. Only the virtual window (visible + overscan ~8 rows) is rendered/measured.
+
+### 5.4 Load-older without jump
+On `onReachTop`, `ConversationPage` grows `displayCount` (prepending older rows).
+Because prepending shifts indices, `MessageList` preserves position: capture
+`scrollHeight` before the row growth, then after re-render set
+`scrollTop += (newScrollHeight − oldScrollHeight)` in a layout effect keyed on
+"rows grew at the top". Items keep stable keys via `computeKey` (message id). This
+also fixes the second audit gap (older-load jump).
+
+## 6. Preserved Behaviors
+
+| Behavior | New mechanism |
+|---|---|
+| Open → bottom / saved row | `initialAnchor` applied in `useLayoutEffect` before reveal |
+| New message while at bottom → follow | stick-to-bottom controller |
+| New message while scrolled up → pill | `onAtBottomChange` drives the existing pill |
+| Unread divider | computed before reveal → no later height change |
+| Load older (scroll to top) | `onReachTop` + scrollHeight-delta preservation |
+| Jump-to-message / search / pin | imperative `scrollToRow(index, align)` |
+| Pending (outbox) bubbles | stay as a row kind in the same list |
+| Per-conversation scroll memory | unchanged module-scoped `scrollPositions` map, fed by `onAtBottomChange` + `onTopRowChange` |
+
+## 7. Interface
+
+```ts
+export interface MessageListHandle {
+  scrollToBottom(behavior?: 'auto' | 'smooth'): void;
+  scrollToRow(index: number, align?: 'center' | 'end', behavior?: 'auto' | 'smooth'): void;
+}
+
+export interface MessageListProps {
+  rows: VirtuosoRow[];                              // loader | message | pending
+  renderRow: (index: number, row: VirtuosoRow) => React.ReactNode;
+  computeKey: (row: VirtuosoRow) => string;        // message id / pending id / '__loader__'
+  initialAnchor: { type: 'bottom' } | { type: 'row'; index: number };
+  ready: boolean;                                  // reveal gate (§5.1)
+  estimateRowHeight?: number;                      // default ~64
+  atBottomThreshold?: number;                      // default 64px
+  onReachTop(): void;                              // load older
+  onAtBottomChange(atBottom: boolean): void;
+  onTopRowChange(topIndex: number): void;          // scroll memory
+}
+```
+
+## 8. Error Handling / Edge Cases
+
+- Empty conversation: `rows.length === 0` → `MessageList` renders nothing; `ready`
+  short-circuits to the existing empty state in `ConversationPage`.
+- Single / very short conversation (content < viewport): bottom-anchor is a no-op;
+  reveal immediately.
+- Rapid chat switching: each switch remounts `ConversationPage` (per-id key) → a
+  fresh `MessageList` instance with fresh measurements (no stale sizes carried over).
+- Very large `displayCount` after deep back-scroll: only the virtual window renders;
+  memory bounded by overscan.
+- Reactions fetch error/empty: max-timeout reveals the list anyway.
+
+## 9. Testing
+
+- **Unit (vitest):** `scrollController.ts` pure functions — anchor resolution,
+  should-auto-scroll decision, load-older offset math, at-bottom threshold.
+- **Manual (dev):** iterate in `pnpm desktop:dev` with the temporary `SCROLL_DEBUG`
+  logging until chat-switch is flicker-free and all §6 behaviors verified live.
+- No automated DOM/layout test (jsdom has no layout); the running app is the test.
+
+## 10. Rollout
+
+1. Add `@tanstack/react-virtual`.
+2. Build `scrollController.ts` (+ tests) and `MessageList.tsx`.
+3. Swap the `<Virtuoso>` block in `ConversationPage` for `<MessageList>`; add the
+   `ready` flag to `useMessageReactions`.
+4. Verify in dev with the user (flicker-free + all behaviors).
+5. Remove the `SCROLL_DEBUG` instrumentation and the `react-virtuoso` dependency.
+6. Release **0.21.6** to `update.netralax.de` (served on `.de` + `.cloud`).
+
+## 11. Out of Scope
+
+Composer, header, dialogs, calls, search UI, message rendering (`MessageBubble`),
+encryption/data layer, mobile app. Reaction/receipt *data* loading is touched only to
+add the `ready` flag for the reveal gate.
+
+## 12. Open Risks
+
+- TanStack prepend position-preservation needs careful layout-effect timing; mitigated
+  by dev iteration before release.
+- The `ready` reveal adds a brief (≤300 ms) spinner on chat open even for cached
+  chats; acceptable trade-off vs flicker. A future in-memory reaction cache could make
+  revisits instant (not in this scope).

pnpm-lock.yaml

@@ -65,6 +65,9 @@ importers:
       '@supabase/supabase-js':
         specifier: ^2.46.0
         version: 2.103.3
+      '@tanstack/react-virtual':
+        specifier: ^3.10.0
+        version: 3.14.2(react-dom@18.3.1(react@18.3.1))(react@18.3.1)
       better-sqlite3:
         specifier: ^11.3.0
         version: 11.10.0
@@ -98,9 +101,6 @@ importers:
       react-router-dom:
         specifier: ^6.28.0
         version: 6.30.3(react-dom@18.3.1(react@18.3.1))(react@18.3.1)
-      react-virtuoso:
-        specifier: ^4.18.7
-        version: 4.18.7(react-dom@18.3.1(react@18.3.1))(react@18.3.1)
       zustand:
         specifier: ^5.0.1
         version: 5.0.12(@types/react@18.3.28)(react@18.3.1)(use-sync-external-store@1.6.0(react@18.3.1))
@@ -1915,6 +1915,15 @@ packages:
     resolution: {integrity: sha512-4BAffykYOgO+5nzBWYwE3W90sBgLJoUPRWWcL8wlyiM8IB8ipJz3UMJ9KXQd1RKQXpKp8Tutn80HZtWsu2u76w==}
     engines: {node: '>=10'}
 
+  '@tanstack/react-virtual@3.14.2':
+    resolution: {integrity: sha512-IpWnmCLvuymRfeeLNVXIzNEYBFLpd3drVIS91sqV78VTZFyldlChkOocZRCPp1B+Wnk09bcLNme8WaMU/9/9bQ==}
+    peerDependencies:
+      react: ^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0
+      react-dom: ^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0
+
+  '@tanstack/virtual-core@3.17.0':
+    resolution: {integrity: sha512-gOxY/hFkPh/XQYhnThBHzkbkX3Ed+z/iushyz+R+JAr213aXxUDgQoTgTdrDpBSRsjFM73P/KfUyWmaF9WHMkQ==}
+
   '@testing-library/react-native@12.9.0':
     resolution: {integrity: sha512-wIn/lB1FjV2N4Q7i9PWVRck3Ehwq5pkhAef5X5/bmQ78J/NoOsGbVY2/DG5Y9Lxw+RfE+GvSEh/fe5Tz6sKSvw==}
     deprecated: React Native Testing Library v12 is no longer maintained. Please upgrade to v13 or v14.
@@ -5479,12 +5488,6 @@ packages:
     peerDependencies:
       react: ^18.3.1
 
-  react-virtuoso@4.18.7:
-    resolution: {integrity: sha512-xNF5zDGEEIMB7cKwcen/pLig0YDf6OnfFrVgKFa7sHPf9fRem0CaLshyObbBcP88jzn0enavL39EgplgdyT21g==}
-    peerDependencies:
-      react: '>=16 || >=17 || >= 18 || >= 19'
-      react-dom: '>=16 || >=17 || >= 18 || >=19'
-
   react@18.3.1:
     resolution: {integrity: sha512-wS+hAgJShR0KhEvPJArfuPVN1+Hz1t0Y6n5jLrGQbkb4urgPE/0Rve+1kMB1v/oWgHgm4WIcV+i7F2pTVj+2iQ==}
     engines: {node: '>=0.10.0'}
@@ -8760,6 +8763,14 @@ snapshots:
     dependencies:
       defer-to-connect: 2.0.1
 
+  '@tanstack/react-virtual@3.14.2(react-dom@18.3.1(react@18.3.1))(react@18.3.1)':
+    dependencies:
+      '@tanstack/virtual-core': 3.17.0
+      react: 18.3.1
+      react-dom: 18.3.1(react@18.3.1)
+
+  '@tanstack/virtual-core@3.17.0': {}
+
   '@testing-library/react-native@12.9.0(react-native@0.76.9(@babel/core@7.29.0)(@babel/preset-env@7.29.2(@babel/core@7.29.0))(@types/react@18.3.28)(encoding@0.1.13)(react@18.3.1))(react-test-renderer@18.3.1(react@18.3.1))(react@18.3.1)':
     dependencies:
       jest-matcher-utils: 29.7.0
@@ -12972,11 +12983,6 @@ snapshots:
       react-shallow-renderer: 16.15.0(react@18.3.1)
       scheduler: 0.23.2
 
-  react-virtuoso@4.18.7(react-dom@18.3.1(react@18.3.1))(react@18.3.1):
-    dependencies:
-      react: 18.3.1
-      react-dom: 18.3.1(react@18.3.1)
-
   react@18.3.1:
     dependencies:
       loose-envify: 1.4.0

scripts/migrate/04-restore-storage-xattrs.py

@@ -0,0 +1,127 @@
+#!/usr/bin/env python3
+# Incident fix (2026-06-02): after the netralax.cloud -> netralax.de move, every
+# storage object GET returned HTTP 500 with:
+#     { "code": "ENODATA", "errno": 61, "message": "The extended attribute does not exist." }
+#
+# Root cause: the OBJECT BYTES were copied to the new server, but Supabase
+# Storage (supabase/storage-api:v1.48.26, file backend) keeps each object's
+# response metadata in Linux extended attributes (xattrs) on the version file:
+#     user.supabase.content-type
+#     user.supabase.cache-control
+#     user.supabase.etag
+# The migration copy did not preserve xattrs, so storage's getObject() throws
+# ENODATA when it reads them. The OLD server is gone, so we cannot re-copy —
+# but every value we need is still in the database column storage.objects.metadata
+# (mimetype / cacheControl / eTag). This script reconstructs the missing xattrs
+# from that column. It is idempotent and only ADDS metadata xattrs; it never
+# touches object bytes.
+#
+# RUN ON THE NEW SERVER (needs /opt/supabase, docker, and root for setxattr):
+#     sudo python3 04-restore-storage-xattrs.py            # all buckets
+#     sudo python3 04-restore-storage-xattrs.py --dry-run  # show, change nothing
+#     sudo python3 04-restore-storage-xattrs.py --bucket profile-avatars
+# After it finishes, no storage restart is needed (xattrs are read per request).
+
+import argparse
+import json
+import os
+import subprocess
+import sys
+
+SUPABASE_DIR = "/opt/supabase"
+# Single-tenant self-hosted layout: <volume>/stub/stub/<bucket>/<name>/<version-file>
+STORAGE_ROOT = os.path.join(SUPABASE_DIR, "volumes/storage/stub/stub")
+
+# DB metadata field  ->  (xattr name, default when the field is absent)
+XATTRS = [
+    ("mimetype", "user.supabase.content-type", "application/octet-stream"),
+    ("cacheControl", "user.supabase.cache-control", "no-cache"),
+    ("eTag", "user.supabase.etag", None),  # None default => skip if missing
+]
+
+
+def fetch_objects():
+    """Return [(bucket_id, name, metadata_dict), ...] from storage.objects."""
+    # Tab-separate so object names containing '|' can't break parsing.
+    query = (
+        "select bucket_id||chr(9)||name||chr(9)||coalesce(metadata::text,'{}') "
+        "from storage.objects"
+    )
+    raw = subprocess.check_output(
+        [
+            "docker", "compose", "exec", "-T", "db",
+            "psql", "-U", "postgres", "-d", "postgres", "-tAc", query,
+        ],
+        cwd=SUPABASE_DIR,
+    ).decode()
+    rows = []
+    for line in raw.splitlines():
+        line = line.rstrip("\r")
+        if not line.strip():
+            continue
+        parts = line.split("\t", 2)
+        if len(parts) < 3:
+            continue
+        bucket, name, meta = parts
+        try:
+            md = json.loads(meta) if meta else {}
+        except json.JSONDecodeError:
+            md = {}
+        rows.append((bucket, name, md))
+    return rows
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--bucket", help="only this bucket (e.g. profile-avatars)")
+    ap.add_argument("--dry-run", action="store_true", help="print, change nothing")
+    args = ap.parse_args()
+
+    objects = fetch_objects()
+    fixed = missing_dir = missing_file = 0
+
+    for bucket, name, md in objects:
+        if args.bucket and bucket != args.bucket:
+            continue
+        objdir = os.path.join(STORAGE_ROOT, bucket, name)
+        if not os.path.isdir(objdir):
+            print("NO_DIR  ", bucket, name)
+            missing_dir += 1
+            continue
+        version_files = [
+            os.path.join(objdir, f)
+            for f in os.listdir(objdir)
+            if os.path.isfile(os.path.join(objdir, f))
+        ]
+        if not version_files:
+            print("NO_FILE ", bucket, name)
+            missing_file += 1
+            continue
+        for path in version_files:
+            for field, xattr, default in XATTRS:
+                value = md.get(field, default)
+                if value is None:
+                    continue
+                if args.dry_run:
+                    print(f"  would set {xattr}={value!r} on {path}")
+                else:
+                    os.setxattr(path, xattr, str(value).encode())
+            fixed += 1
+        print("OK      ", bucket, name)
+
+    print(
+        f"\n{'DRY-RUN: would fix' if args.dry_run else 'fixed'} {fixed} file(s); "
+        f"{missing_dir} missing dir(s), {missing_file} empty object dir(s)."
+    )
+    if missing_dir or missing_file:
+        print(
+            "NOTE: objects with a missing dir/file have lost their bytes and "
+            "cannot be recovered from xattrs — those are genuinely gone."
+        )
+
+
+if __name__ == "__main__":
+    if os.geteuid() != 0 and "--dry-run" not in sys.argv:
+        print("Re-run with sudo (setxattr needs root).", file=sys.stderr)
+        sys.exit(1)
+    main()