feat: implement tag CRUD UI

lib/providers.dart

@@ -145,6 +145,19 @@ final sensorProvider =
   return ref.watch(sensorRepositoryProvider).getSensor(id);
 });
 
+// ---------------------------------------------------------------------------
+// Tag data
+// ---------------------------------------------------------------------------
+
+final tagsProvider = FutureProvider.autoDispose<List<Tag>>((ref) {
+  return ref.watch(tagRepositoryProvider).getTags();
+});
+
+final tagProvider =
+    FutureProvider.autoDispose.family<Tag, int>((ref, id) {
+  return ref.watch(tagRepositoryProvider).getTag(id);
+});
+
 // ---------------------------------------------------------------------------
 // Cross-tab UI state
 // ---------------------------------------------------------------------------
@@ -171,6 +184,12 @@ final tagPositionsProvider = StreamProvider<List<TagPosition>>((ref) {
   return repo.watchPositions();
 });
 
+/// Accumulated room occupancy: room_id → [tag_id, ...].
+/// Updated incrementally as `occupancy_changed` events arrive on rooms:occupancy.
+final roomOccupancyProvider = StreamProvider<Map<int, List<String>>>((ref) {
+  return ref.watch(tagRepositoryProvider).watchRoomOccupancy();
+});
+
 final particleCloudProvider = StreamProvider<List<Particle>>((ref) {
   final repo = ref.watch(tagRepositoryProvider);
   return repo.watchParticleCloud();