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/ringtone.ts

@@ -1,6 +1,13 @@
-// Looping WebAudio ringtones. Two patterns:
-//   - outgoing: long calling tone, 3s cycle
-//   - incoming: classic "ring ring" double beep, 2s cycle
+// Looping ringtones. Two patterns:
+//   - outgoing: long calling tone, 3s cycle (oscillator only)
+//   - incoming: classic "ring ring" double beep (oscillator), optionally
+//     upgraded to a user-supplied audio file stored in ringtoneStorage
+//
+// The custom file plays immediately if we can load it; otherwise we fall
+// back to the generated oscillator pattern so ringing never misses an
+// incoming call due to an IO failure.
+
+import { getIncomingRingtone } from './ringtoneStorage';
 
 type Pattern = 'outgoing' | 'incoming';
 
@@ -9,15 +16,90 @@ class Ringtone {
   private interval: number | null = null;
   private pattern: Pattern | null = null;
 
+  // Custom-file playback path (incoming only).
+  private audioEl: HTMLAudioElement | null = null;
+  private customUrl: string | null = null;
+  // Sequence token to ignore slow IO completing after user changed state.
+  private startSeq = 0;
+
   start(pattern: Pattern): void {
     if (this.pattern === pattern) return; // already playing this pattern
     this.stop();
+    this.pattern = pattern;
+    const seq = ++this.startSeq;
+
+    if (pattern === 'incoming') {
+      // Kick off oscillator immediately so we never miss ringing feedback
+      // while the custom file (if any) loads asynchronously. Once the blob
+      // is ready we hand playback over to the <audio> element.
+      this.startOscillator(pattern);
+      void this.tryUpgradeToCustom(seq);
+    } else {
+      this.startOscillator(pattern);
+    }
+  }
+
+  stop(): void {
+    this.startSeq++;
+    this.stopOscillator();
+    this.stopCustom();
+    this.pattern = null;
+  }
+
+  // --- Custom file path (incoming only) ----------------------------------
+
+  private async tryUpgradeToCustom(seq: number): Promise<void> {
+    let stored;
+    try {
+      stored = await getIncomingRingtone();
+    } catch {
+      return; // keep oscillator
+    }
+    // User stopped or switched patterns while we were loading.
+    if (seq !== this.startSeq || this.pattern !== 'incoming' || !stored) return;
+
+    const url = URL.createObjectURL(stored.blob);
+    const el = new Audio(url);
+    el.loop = true;
+    el.volume = 0.85;
+    // Chrome/WKWebView autoplay policy: muted playback is always allowed,
+    // but ringtones must be audible, so play() may reject the first time
+    // before the user interacted. If it rejects, we keep the oscillator.
+    el.play().catch(() => {
+      URL.revokeObjectURL(url);
+    });
+
+    this.audioEl = el;
+    this.customUrl = url;
+    // Only swap off the oscillator once the custom element is actually
+    // wired — avoids a silent gap on transition.
+    this.stopOscillator();
+  }
+
+  private stopCustom(): void {
+    if (this.audioEl) {
+      try {
+        this.audioEl.pause();
+      } catch {
+        /* ignore */
+      }
+      this.audioEl.src = '';
+      this.audioEl = null;
+    }
+    if (this.customUrl) {
+      URL.revokeObjectURL(this.customUrl);
+      this.customUrl = null;
+    }
+  }
+
+  // --- Oscillator fallback ----------------------------------------------
+
+  private startOscillator(pattern: Pattern): void {
     const AudioCtx =
       window.AudioContext ??
       (window as unknown as { webkitAudioContext?: typeof AudioContext }).webkitAudioContext;
     if (!AudioCtx) return;
     this.ctx = new AudioCtx();
-    this.pattern = pattern;
 
     const play = pattern === 'outgoing' ? this.playOutgoing : this.playIncoming;
     play.call(this);
@@ -27,7 +109,7 @@ class Ringtone {
     );
   }
 
-  stop(): void {
+  private stopOscillator(): void {
     if (this.interval !== null) {
       window.clearInterval(this.interval);
       this.interval = null;
@@ -38,7 +120,6 @@ class Ringtone {
       });
       this.ctx = null;
     }
-    this.pattern = null;
   }
 
   private beep(freq: number, durationSec: number, delaySec: number, gain = 0.18): void {