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.

frontend/src/lib/i18n/en.json

@@ -523,6 +523,9 @@
 		"memorySource": "Memory source",
 		"memorySourceAlbums": "Scan tracked albums",
 		"memorySourceNative": "Immich native memories",
+		"quietHours": "Quiet hours",
+		"quietHoursStart": "Start",
+		"quietHoursEnd": "End",
 		"test": "Test",
 		"confirmDelete": "Delete this tracking config?",
 		"sortNone": "None",
@@ -670,6 +673,8 @@
 		"webhookSecretHint": "Secret token to verify webhook requests from Telegram",
 		"cacheTtl": "Media Cache TTL (hours)",
 		"cacheTtlHint": "How long to cache uploaded Telegram file_ids before re-uploading",
+		"timezone": "Timezone",
+		"timezoneHint": "IANA timezone (e.g. UTC, Europe/Warsaw, America/New_York). Used to interpret HH:MM fields like quiet hours.",
 		"locales": "Template Languages",
 		"supportedLocales": "Supported Locales",
 		"supportedLocalesHint": "Comma-separated locale codes for template editing (e.g. en,ru,de,fr)",
@@ -680,6 +685,7 @@
 		"scheduledAssets": "Sends random or selected photos from tracked albums on a schedule. Like a daily photo pick.",
 		"memoryMode": "\"On This Day\" — sends photos taken on this date in previous years. Nostalgic flashbacks.",
 		"memorySource": "Albums: scans tracked albums for date-matching assets. Native: uses Immich's built-in memories (covers entire library, optionally filtered by tracked albums).",
+		"quietHours": "Suppress all notifications during this HH:MM window (interpreted in the app timezone). Overnight windows like 22:00–07:00 are supported.",
 		"favoritesOnly": "Only include assets marked as favorites.",
 		"maxAssets": "Maximum number of asset details to include in a single notification message.",
 		"periodicStartDate": "The reference date for calculating periodic intervals. Summaries are sent every N days from this date.",