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/seeds.py

@@ -151,6 +151,7 @@ async def _seed_default_templates() -> None:
         await _seed_provider_template(session, "gitea", "Gitea")
         await _seed_provider_template(session, "planka", "Planka")
         await _seed_provider_template(session, "scheduler", "Scheduler")
+        await _seed_provider_template(session, "nut", "NUT")
         await session.commit()
 
 
@@ -171,6 +172,9 @@ async def _seed_default_command_templates() -> None:
         await _seed_provider_command_template(
             session, "planka", "Default Planka Commands", "Default Planka command templates",
         )
+        await _seed_provider_command_template(
+            session, "nut", "Default NUT Commands", "Default NUT command templates",
+        )
         await session.commit()
 
 
@@ -221,6 +225,18 @@ async def _seed_default_tracking_configs() -> None:
                 "name": "Default Scheduler",
                 "track_scheduled_message": True,
             },
+            {
+                "provider_type": "nut",
+                "name": "Default NUT",
+                "track_ups_online": True,
+                "track_ups_on_battery": True,
+                "track_ups_low_battery": True,
+                "track_ups_battery_restored": True,
+                "track_ups_comms_lost": True,
+                "track_ups_comms_restored": True,
+                "track_ups_replace_battery": True,
+                "track_ups_overload": True,
+            },
         ]
 
         for cfg in defaults:
@@ -279,6 +295,16 @@ async def _seed_default_command_configs() -> None:
                 "default_count": 10,
                 "rate_limits": {"api": 15, "default": 10},
             },
+            {
+                "provider_type": "nut",
+                "name": "Default NUT",
+                "enabled_commands": [
+                    "help", "status", "devices", "battery",
+                ],
+                "response_mode": "text",
+                "default_count": 5,
+                "rate_limits": {"api": 15, "default": 10},
+            },
         ]
 
         for cfg in defaults: