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

DB
- Added user pref columns; vibration is per-channel
  (vibrationEnabledOrder + vibrationEnabledMeeting). Defaults: ding/chime
  sounds, vibration on, mute off. Volume uses the device system level —
  no persisted volume field.

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 + 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). Skipped
  when the tab is currently visible — sound only fires when backgrounded.
- AR/EN translations added.

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

lib/api-zod/src/generated/api.ts

@@ -79,7 +79,6 @@ export const LoginResponse = zod.object({
   vibrationEnabledOrder: zod.boolean(),
   vibrationEnabledMeeting: zod.boolean(),
   notificationsMuted: zod.boolean(),
-  notificationVolume: zod.number(),
   roles: zod.array(zod.string()),
   groups: zod.array(
     zod.object({
@@ -193,7 +192,6 @@ export const GetMeResponse = zod.object({
   vibrationEnabledOrder: zod.boolean(),
   vibrationEnabledMeeting: zod.boolean(),
   notificationsMuted: zod.boolean(),
-  notificationVolume: zod.number(),
   roles: zod.array(zod.string()),
   groups: zod.array(
     zod.object({
@@ -256,7 +254,6 @@ export const UpdateLanguageResponse = zod.object({
   vibrationEnabledOrder: zod.boolean(),
   vibrationEnabledMeeting: zod.boolean(),
   notificationsMuted: zod.boolean(),
-  notificationVolume: zod.number(),
   roles: zod.array(zod.string()),
   groups: zod.array(
     zod.object({
@@ -326,7 +323,6 @@ export const UpdateClockStyleResponse = zod.object({
   vibrationEnabledOrder: zod.boolean(),
   vibrationEnabledMeeting: zod.boolean(),
   notificationsMuted: zod.boolean(),
-  notificationVolume: zod.number(),
   roles: zod.array(zod.string()),
   groups: zod.array(
     zod.object({
@@ -342,9 +338,6 @@ export const UpdateClockStyleResponse = zod.object({
 /**
  * @summary Update notification sound, vibration & mute preferences
  */
-export const updateNotificationPreferencesBodyNotificationVolumeMin = 0;
-export const updateNotificationPreferencesBodyNotificationVolumeMax = 100;
-
 export const UpdateNotificationPreferencesBody = zod.object({
   notificationSoundOrder: zod
     .enum(["ding", "chime", "bell", "knock", "pop", "alert", "beep", "soft"])
@@ -357,11 +350,6 @@ export const UpdateNotificationPreferencesBody = zod.object({
   vibrationEnabledOrder: zod.boolean().optional(),
   vibrationEnabledMeeting: zod.boolean().optional(),
   notificationsMuted: zod.boolean().optional(),
-  notificationVolume: zod
-    .number()
-    .min(updateNotificationPreferencesBodyNotificationVolumeMin)
-    .max(updateNotificationPreferencesBodyNotificationVolumeMax)
-    .optional(),
 });
 
 export const UpdateNotificationPreferencesResponse = zod.object({
@@ -407,7 +395,6 @@ export const UpdateNotificationPreferencesResponse = zod.object({
   vibrationEnabledOrder: zod.boolean(),
   vibrationEnabledMeeting: zod.boolean(),
   notificationsMuted: zod.boolean(),
-  notificationVolume: zod.number(),
   roles: zod.array(zod.string()),
   groups: zod.array(
     zod.object({
@@ -475,7 +462,6 @@ export const UpdateClockHour12Response = zod.object({
   vibrationEnabledOrder: zod.boolean(),
   vibrationEnabledMeeting: zod.boolean(),
   notificationsMuted: zod.boolean(),
-  notificationVolume: zod.number(),
   roles: zod.array(zod.string()),
   groups: zod.array(
     zod.object({