feat(tracking): per-config quiet hours with app-level IANA timezone

Add quiet_hours_enabled/start/end to TrackingConfig (HH:MM strings
interpreted in the app-level timezone AppSetting). The dispatch path
loads the app timezone once per run and passes it through
event_allowed_by_config -> in_quiet_hours, so overnight windows like
22:00-07:00 work correctly in any IANA tz.

Frontend exposes a Timezone field under Settings and a Quiet Hours
section on the Immich tracking-config form with time-picker inputs.

packages/server/src/notify_bridge_server/api/app_settings.py

@@ -22,6 +22,7 @@ _SETTING_KEYS = {
     "telegram_webhook_secret": "NOTIFY_BRIDGE_TELEGRAM_WEBHOOK_SECRET",
     "telegram_cache_ttl_hours": None,  # no env fallback, default 48
     "supported_locales": None,  # comma-separated locale codes
+    "timezone": "NOTIFY_BRIDGE_TIMEZONE",  # IANA tz (e.g. "Europe/Warsaw"); empty = UTC
 }
 
 _DEFAULTS = {
@@ -29,6 +30,7 @@ _DEFAULTS = {
     "telegram_webhook_secret": "",
     "telegram_cache_ttl_hours": "48",
     "supported_locales": "en,ru",
+    "timezone": "UTC",
 }
 
 
@@ -50,6 +52,7 @@ class SettingsUpdate(BaseModel):
     telegram_webhook_secret: str | None = None
     telegram_cache_ttl_hours: str | None = None
     supported_locales: str | None = None
+    timezone: str | None = None
 
 
 @router.get("")