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/lib/globalShortcut.ts

@@ -55,3 +55,72 @@ export async function unregisterPttShortcut(code: string): Promise<void> {
 export function isTauriRuntime(): boolean {
   return typeof window !== 'undefined' && '__TAURI_INTERNALS__' in window;
 }
+
+// --- Soundboard shortcuts --------------------------------------------------
+//
+// Separate from the single PTT shortcut: the soundboard needs to register
+// many fire-and-forget press bindings at once, keep track of which ids own
+// which accelerators so we can unregister just one, and expose conflict
+// detection for the settings UI.
+
+interface SoundShortcutRegistration {
+  shortcut: string;
+  onPress: () => void;
+}
+
+// Map of logical id (sound uuid) -> registration.
+const soundRegistry = new Map<string, SoundShortcutRegistration>();
+
+export async function registerSoundShortcut(
+  id: string,
+  code: string,
+  onPress: () => void,
+): Promise<boolean> {
+  if (!isTauriRuntime()) return false;
+  const shortcut = codeToShortcut(code);
+  // Unregister any previous binding for this id first — caller may be
+  // re-registering after the user changed the hotkey for the same sound.
+  await unregisterSoundShortcut(id);
+  try {
+    if (await isRegistered(shortcut)) {
+      await unregister(shortcut);
+    }
+    await register(shortcut, (event: ShortcutEvent) => {
+      if (event.state === 'Pressed') onPress();
+    });
+    soundRegistry.set(id, { shortcut, onPress });
+    return true;
+  } catch (err: unknown) {
+    console.warn('registerSoundShortcut failed', { id, code, err });
+    return false;
+  }
+}
+
+export async function unregisterSoundShortcut(id: string): Promise<void> {
+  const reg = soundRegistry.get(id);
+  if (!reg) return;
+  soundRegistry.delete(id);
+  if (!isTauriRuntime()) return;
+  try {
+    if (await isRegistered(reg.shortcut)) {
+      await unregister(reg.shortcut);
+    }
+  } catch (err: unknown) {
+    console.warn('unregisterSoundShortcut failed', { id, err });
+  }
+}
+
+export async function unregisterAllSoundShortcuts(): Promise<void> {
+  const ids = Array.from(soundRegistry.keys());
+  await Promise.all(ids.map((id) => unregisterSoundShortcut(id)));
+}
+
+// Resolve a DOM code to the registry's current owner (if any). Used by the
+// settings UI to surface conflicts before saving a new hotkey.
+export function soundShortcutOwnerFor(code: string): string | null {
+  const shortcut = codeToShortcut(code);
+  for (const [id, reg] of soundRegistry) {
+    if (reg.shortcut === shortcut) return id;
+  }
+  return null;
+}