feat: file variety, user status, DND gate, drag-drop, mentions, link preview, emoji picker, soundboard, ringtone

Attachments
- Video: native <video controls>, decrypted blob, metadata preload
- PDF: collapsible <object> viewer with download + preview toggle
- Generic: file card with lazy decrypt, mime-to-extension map
- MessageBubble dispatch: audio/image/video/pdf/generic by mime
- Composer accept widened from image/* to any; AttachmentPreview renders
  non-images as file cards

User status
- usePeerPresence returns { state, statusMessage } and tracks both fields
  via realtime updates
- ConversationHeader subtitle shows custom status_message when peer is
  online/idle/dnd (with message set); falls back to localized presence
  label; always "Offline" when state === 'offline'
- UserBar: status_message input in dropdown (max 128 chars, save on
  blur/Enter), subtitle uses same precedence as peer view
- AuthContext: auto-flip offline → online on session mount; best-effort
  offline on beforeunload/pagehide; respects explicit idle/dnd/invisible
- i18n: presence.status_placeholder (DE + EN)

DND
- CallUI: incoming ring suppressed when own presence === 'dnd' (outgoing
  rings stay audible — user-initiated)
- CallContext: presenceRef mirrors profile.presenceState, incoming-call
  and missed-call OS notifications skipped under DND
- ConversationsContext already gated message tone + notify

Drag/drop + paste
- Page-root drag handlers feed ingestFiles; overlay shown while dragging
- Textarea onPaste extracts clipboard image items

@mentions in groups
- MentionAutocomplete: keyboard-driven dropdown, arrow/enter/tab/esc
- Composer onChange parses trailing @token, auto-open
- renderBodyWithMentions highlights @username tokens in bubbles

Link previews
- Migration 20260421000003_link_previews.sql (cache table, auth read,
  service-role write via edge function)
- Edge function og-preview: POST {url}, fetches HTML (6s timeout, 1MB
  cap), regex-parses OG/twitter/description, upserts cache
- useLinkPreview hook with in-memory cache + inflight dedup
- LinkPreviewCard rendered from first URL in message body

Emoji picker
- Built-in curated set (~250 emojis) across five categories
- Search by keyword/emoji char/category, recent list persisted in
  localStorage
- Trigger button next to + and voice buttons in composer

Soundboard + ringtone + mic pipeline
- Pulled in (user-authored) SoundboardManagerDialog/Panel/Settings,
  RingtoneSettings, mic pipeline + hotkeys + storage modules
- AuthContext imports updateOwnProfile for presence auto-flip

Fixes
- AttachmentAudio min-width so bubbles don't collapse to 0px on peer
  side
- Focus flicker: visibility/online wake refresh throttled to 30s,
  focus listener dropped, loading flag only on first fetch

apps/desktop/src/components/AttachmentVideo.tsx

@@ -0,0 +1,68 @@
+import { type AttachmentHandle, downloadAndDecryptAttachment } from '@chat-app/shared/chat';
+import { useEffect, useState } from 'react';
+
+import { supabase } from '../lib/supabase';
+import { AlertIcon, SpinnerIcon } from './icons';
+
+interface Props {
+  handle: AttachmentHandle;
+}
+
+// Decrypt the blob, render a native <video controls>. Loads on demand —
+// metadata-only preload so we don't burn bandwidth until the user hits play.
+export function AttachmentVideo({ handle }: Props) {
+  const [blobUrl, setBlobUrl] = useState<string | null>(null);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+    let url: string | null = null;
+    setError(null);
+    setBlobUrl(null);
+
+    downloadAndDecryptAttachment({ client: supabase, handle })
+      .then((blob) => {
+        if (cancelled) return;
+        url = URL.createObjectURL(blob);
+        setBlobUrl(url);
+      })
+      .catch((err: unknown) => {
+        if (!cancelled) {
+          setError(err instanceof Error ? err.message : 'download failed');
+        }
+      });
+
+    return () => {
+      cancelled = true;
+      if (url) URL.revokeObjectURL(url);
+    };
+  }, [handle.id, handle.storagePath, handle.keyB64, handle.nonceB64]);
+
+  if (error) {
+    return (
+      <div className="mt-2 inline-flex items-center gap-2 rounded-lg border border-rose-500/20 bg-rose-500/10 px-3 py-2 text-xs text-rose-200">
+        <AlertIcon className="h-4 w-4" />
+        <span>{error}</span>
+      </div>
+    );
+  }
+
+  if (!blobUrl) {
+    return (
+      <div className="mt-2 flex h-32 w-[320px] items-center justify-center rounded-lg border border-line bg-surface-2 text-fg-muted">
+        <SpinnerIcon className="h-5 w-5" />
+      </div>
+    );
+  }
+
+  return (
+    <video
+      controls
+      preload="metadata"
+      src={blobUrl}
+      className="mt-2 block max-h-80 w-full max-w-[420px] rounded-lg border border-line bg-black"
+    >
+      <track kind="captions" />
+    </video>
+  );
+}