feat: NUT (Network UPS Tools) service provider + provider-agnostic UI

Add full NUT support as a polling-based service provider:
- Async TCP client for upsd protocol (port 3493, configurable)
- 8 event types: online, on_battery, low_battery, battery_restored,
  comms_lost, comms_restored, replace_battery, overload
- 3 bot commands: /status, /devices, /battery
- 38 Jinja2 templates (EN+RU notification + command templates)
- Database: tracking config fields, migration, seeds
- Frontend: provider form with host/port/credentials, grid items, i18n

Provider-agnostic UI improvements:
- Remove hardcoded 'immich' defaults from all config forms
- Dynamic collection labels per provider type (Albums/Repos/Boards/UPS Devices)
- Capability-driven test types instead of provider type checks
- Template variable helpers for all providers (was Immich-only)
- Guard Immich-only shared link check to Immich providers
- Auto-clear stale global provider filter from localStorage
- EntitySelect search placeholder shows current selection
- Fix noneLabel in linked target config selectors

New CLAUDE.md rule #8: no provider-specific hardcoding

packages/server/src/notify_bridge_server/database/models.py

@@ -150,6 +150,16 @@ class TrackingConfig(SQLModel, table=True):
     # Scheduler event tracking
     track_scheduled_message: bool = Field(default=True)
 
+    # NUT (UPS) event tracking
+    track_ups_online: bool = Field(default=True)
+    track_ups_on_battery: bool = Field(default=True)
+    track_ups_low_battery: bool = Field(default=True)
+    track_ups_battery_restored: bool = Field(default=True)
+    track_ups_comms_lost: bool = Field(default=True)
+    track_ups_comms_restored: bool = Field(default=True)
+    track_ups_replace_battery: bool = Field(default=True)
+    track_ups_overload: bool = Field(default=True)
+
     # Immich asset display
     track_images: bool = Field(default=True)
     track_videos: bool = Field(default=True)