chore(desktop): drop react-virtuoso + scroll debug instrumentation

apps/desktop/package.json

@@ -36,7 +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/pages/ConversationPage.tsx

@@ -110,21 +110,6 @@ const EMPTY_REACTIONS: AggregatedReaction[] = [];
 // reading position even if some rows above re-render at different heights.
 const scrollPositions = new Map<string, { topmostIndex: number; stickToBottom: boolean }>();
 
-// ── TEMP scroll-jank instrumentation ──────────────────────────────────────
-// Flip SCROLL_DEBUG to false or delete this block once the chat-switch flicker
-// is root-caused. Logs go to the devtools console AND window.__scrolllog (copy
-// the whole run with: copy(window.__scrolllog.join('\n')) ).
-const SCROLL_DEBUG = true;
-const dbgNow = (): number => Math.round(performance.now());
-const dbgLog = (line: string): void => {
-  if (!SCROLL_DEBUG) return;
-  const w = window as unknown as { __scrolllog?: string[] };
-  (w.__scrolllog ??= []).push(line);
-  // eslint-disable-next-line no-console
-  console.log(line);
-};
-// ──────────────────────────────────────────────────────────────────────────
-
 /** Pending composer attachment: the raw File plus the per-attachment
  *  view-once flag the user can toggle from the thumb hover button (P7.T4).
  *  Lives only in composer state — the flag is forwarded into
@@ -506,18 +491,6 @@ export function ConversationPage() {
     return { type: 'bottom' };
   }, []);
 
-  // SCROLL_DEBUG: log every render with the height-affecting inputs so the
-  // post-mount cascade (reactions/pins/receipts/divider/refresh) is visible.
-  useEffect(() => {
-    dbgLog(
-      `[scroll] render t=${dbgNow()} id=${(id ?? '').slice(0, 6)} loading=${loading}` +
-        ` msgs=${messages.length} rows=${virtuosoRows.length} ready=${listReady}` +
-        ` reactions=${reactionsByMessage.size} pins=${pins.length}` +
-        ` firstUnread=${firstUnreadId ? 'set' : '-'}` +
-        ` displayCount=${displayCount} anchor=${JSON.stringify(initialAnchor)}`,
-    );
-  });
-
   const jumpToMessage = useCallback(
     (targetId: string) => {
       const msgIdx = messages.findIndex((m) => m.id === targetId);
@@ -720,7 +693,6 @@ export function ConversationPage() {
   // away counter when the user actually reaches the bottom.
   const handleAtBottomStateChange = useCallback(
     (atBottom: boolean) => {
-      dbgLog(`[scroll] atBottom=${atBottom} t=${dbgNow()}`);
       setStickToBottom(atBottom);
       if (atBottom) setNewMessagesWhileAway(0);
       if (id) {
@@ -739,7 +711,6 @@ export function ConversationPage() {
   // we only care about the start of the range here.
   const handleRangeChanged = useCallback(
     (range: { startIndex: number; endIndex: number }) => {
-      dbgLog(`[scroll] range t=${dbgNow()} start=${range.startIndex} end=${range.endIndex}`);
       topmostIndexRef.current = range.startIndex;
       if (id) {
         const prev = scrollPositions.get(id);