[03-Developer] #226 Catalog Gallery 구현

- Drift schema v2: Protocols.category CHECK 6→7 (light_circadian/sleep/movement/
  nutrition/focus_cognition/recovery_stress/emotion_relationship). schemaVersion
  1→2 + onUpgrade migrateV1ToV2 (DROP+CREATE+reseed flag 클리어).
- protocols.json 34 항목 v2 재분류 (1차 효과 기준). emotion_relationship 0 매핑.
- 도메인: DisplayCategory enum (8) + CatalogItem sealed (Protocol/Break/Diet).
- 데이터: CatalogRepository.all/byId/referencesByIds (3 source 통합).
- 상태: catalog_providers.dart (catalogItems / groupedByCategory / refsByIds).
- UI: ProtocolGalleryScreen (카테고리 칩 + 카드 그리드) + ProtocolPreviewScreen
  (모든 필드 + reference 펼치기 + "내 습관으로" disabled placeholder) +
  CatalogCard / CategoryChipRow / ReferenceExpandCard. HabitListScreen 빈
  상태 CTA + AppBar 액션.
- 테스트: migration_v1_to_v2 3건 + display_category 5건 + catalog_repository
  9건 + gallery widget 3건 + preview widget 3건 = 23 신규. 기존 88 회귀 0,
  flutter analyze 0 issues. 110 passed / 1 skipped.

설계서: docs/design/226-catalog-gallery/{README, fn-catalog_repository,
fn-migration_v1_to_v2}.md + ADR-0004.

Refs #226

app/lib/data/db/daos/habit_dao.g.dart

@@ -9,4 +9,21 @@ mixin _$HabitDaoMixin on DatabaseAccessor<AppDatabase> {
   $HabitsTable get habits => attachedDatabase.habits;
   $HabitDoseVariantsTable get habitDoseVariants =>
       attachedDatabase.habitDoseVariants;
+  HabitDaoManager get managers => HabitDaoManager(this);
+}
+
+class HabitDaoManager {
+  final _$HabitDaoMixin _db;
+  HabitDaoManager(this._db);
+  $$UsersTableTableManager get users =>
+      $$UsersTableTableManager(_db.attachedDatabase, _db.users);
+  $$PhasesTableTableManager get phases =>
+      $$PhasesTableTableManager(_db.attachedDatabase, _db.phases);
+  $$HabitsTableTableManager get habits =>
+      $$HabitsTableTableManager(_db.attachedDatabase, _db.habits);
+  $$HabitDoseVariantsTableTableManager get habitDoseVariants =>
+      $$HabitDoseVariantsTableTableManager(
+        _db.attachedDatabase,
+        _db.habitDoseVariants,
+      );
 }