Task #389: Notification sounds + vibration with per-user customization

DB
- Added 7 user pref columns; vibration is now per-channel
  (vibrationEnabledOrder + vibrationEnabledMeeting). Defaults: ding/chime
  sounds, vibration on, mute off, volume 70.

API
- PATCH /auth/me/notification-preferences (requireAuth, whitelisted partial
  update, integer guard for volume). buildAuthUser exposes all new fields.
- OpenAPI spec updated; orval client + zod regenerated.

Frontend
- Static sound library: 8 short WAV assets under public/sounds/ + manifest
  (notification-sound-manifest.ts) mapping id -> labelKey -> URL.
- HTMLAudio-based player (notification-sounds.ts) with throttle, unlock,
  cache, and AUTOPLAY_BLOCKED_EVENT dispatch when play is denied pre-gesture.
- Settings popover: global mute, volume, slot tabs (orders/meetings) with
  per-channel sound + per-channel vibration + per-channel toggle, sound list
  with one-tap previews. Concurrency-safe optimistic updates (monotonic seq
  counter). RTL-correct toggle knob transforms.
- QuickMuteButton: one-tap topbar mute control (Volume2/VolumeX) with
  confirmation toast.
- useAudioUnlock: unlocks audio on first interaction.
- useAutoplayHint: toasts a localized "click anywhere to enable" hint when
  the player reports a blocked play attempt.
- Socket hook plays the right per-channel sound + vibration on
  notification_created (orders, executive_meeting) when the tab is hidden.
- UpcomingMeetingAlert: plays meeting reminder once per new eligible
  meeting (deduped by meetingId, survives 30s polling refetches).
- AR/EN translations added.

Pre-existing TS errors in executive-meetings.ts (font_settings) and
pre-existing test workflow failures are unrelated.

artifacts/tx-os/src/App.tsx

@@ -5,6 +5,7 @@ import { TooltipProvider } from "@/components/ui/tooltip";
 import { AuthProvider } from "@/contexts/AuthContext";
 import { useNotificationsSocket } from "@/hooks/use-notifications-socket";
 import { useAudioUnlock } from "@/hooks/use-audio-unlock";
+import { useAutoplayHint } from "@/hooks/use-autoplay-hint";
 import { UpcomingMeetingAlert } from "@/components/executive-meetings/upcoming-meeting-alert";
 import NotFound from "@/pages/not-found";
 import LoginPage from "@/pages/login";
@@ -33,6 +34,7 @@ const queryClient = new QueryClient({
 function NotificationsSocketBridge() {
   useNotificationsSocket();
   useAudioUnlock();
+  useAutoplayHint();
   return null;
 }