feat: Home Assistant provider — WebSocket subscription + bot commands

Adds Home Assistant as a service provider with two coordinated surfaces:

Notifications (subscription):
- Long-lived WebSocket client (aiohttp ws_connect) with auth handshake,
  exponential-backoff reconnect, bounded event queue, and area-registry
  enrichment cached per (re)connect
- ServiceProvider ABC gains an optional `subscribe()` method for push-style
  providers; HomeAssistantServiceProvider uses it via a per-provider
  supervisor task started in the FastAPI lifespan
- 4 event types (state_changed, automation_triggered, call_service,
  event_fired), 4 default Jinja templates (en + ru), HA-specific
  tracker filters (entity_glob, domain_allowlist, exact entity ids)
- Extracted shared dispatch pipeline (api/webhooks.py → services/
  event_dispatch.py) so subscription and webhook ingest share the same
  event_log + deferred-dispatch + quiet-hours code path

Bot commands:
- /status, /entities [glob], /state <entity_id>, /areas
- Multi-command WS session so /status and /areas cost one handshake
- Sensitive-attribute blocklist (camera access_token, entity_picture, etc.)
  and 30-attribute cap to keep /state output safe and within Telegram's
  message size
- Error-message redaction strips URL userinfo before surfacing to chat

Frontend:
- HA descriptor with toggle ConfigField type (new) and tag-input filter
  mode for free-text glob/domain lists (new TagInput component)
- 15 command slots + 4 notification slots wired into the existing
  template-config UI

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

@@ -292,6 +292,23 @@ async def migrate_schema(engine: AsyncEngine) -> None:
                 )
                 logger.info("Added track_webhook_received column to tracking_config table")
 
+        # Add Home Assistant tracking flags to tracking_config if missing.
+        # state_changed defaults ON to match the canonical "watch the state bus"
+        # use case; the other three are loud and opt-in (defaults 0).
+        if await _has_table(conn, "tracking_config"):
+            ha_flags = [
+                ("track_ha_state_changed", "INTEGER DEFAULT 1"),
+                ("track_ha_automation_triggered", "INTEGER DEFAULT 0"),
+                ("track_ha_service_called", "INTEGER DEFAULT 0"),
+                ("track_ha_event_fired", "INTEGER DEFAULT 0"),
+            ]
+            for col_name, col_type in ha_flags:
+                if not await _has_column(conn, "tracking_config", col_name):
+                    await conn.execute(
+                        text(f"ALTER TABLE tracking_config ADD COLUMN {col_name} {col_type}")
+                    )
+                    logger.info("Added %s column to tracking_config table", col_name)
+
         # Add quiet hours to tracking_config if missing.
         # Start/end are nullable HH:MM strings; quiet_hours_enabled gates them.
         if await _has_table(conn, "tracking_config"):