chore: release v0.3.3

Features:
- Health check endpoint for Portainer monitoring
- Local search filtering in DataGrid
- Container status badges reflect health (green/orange/blue)

Improvements:
- Standardized 56px header heights across panels
- Container grid parses Docker API format correctly
- Search bar styling improvements
- Status badges have consistent width

Fixes:
- Quick links persistence (link type, form refresh)
- Iframe switching closes existing content first
- ContainerState type conflict resolved

Branding:
- Updated favicon and icons with Tatlock bucket logo

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/ARCHITECTURE.md

@@ -197,6 +197,139 @@ class ContainerRepositoryImpl implements ContainerRepository {
 }
 ```
 
+## Data Model Patterns
+
+Models handle conversion between API JSON and domain entities. The pattern depends on whether the feature is **read-only** or **CRUD**.
+
+### Read-Only Models
+
+For data fetched from external systems (Docker, NPM, Portainer) where Flutter doesn't create/update records:
+
+```dart
+@freezed
+sealed class ContainerModel with _$ContainerModel {
+  const factory ContainerModel({
+    required String id,
+    required String name,
+    required String status,
+  }) = _ContainerModel;
+
+  const ContainerModel._();
+
+  factory ContainerModel.fromJson(Map<String, dynamic> json) =>
+      _$ContainerModelFromJson(json);
+
+  /// Converts API response to domain entity.
+  Container toEntity() => Container(
+    id: id,
+    name: name,
+    status: ContainerStatus.values.byName(status),
+  );
+}
+```
+
+**Only `toEntity()` is needed** - no `fromEntity()` or `toJson()` required.
+
+### CRUD Models (Bidirectional)
+
+For data that Flutter creates, updates, and deletes:
+
+```dart
+@freezed
+sealed class QuickLinkModel with _$QuickLinkModel {
+  const factory QuickLinkModel({
+    @Default(0) int id,
+    required String title,
+    required String url,
+    String? icon,
+    String? category,
+    @Default(0) int position,
+    @JsonKey(name: 'is_visible') @Default(true) bool isVisible,
+  }) = _QuickLinkModel;
+
+  const QuickLinkModel._();
+
+  factory QuickLinkModel.fromJson(Map<String, dynamic> json) =>
+      _$QuickLinkModelFromJson(json);
+
+  /// Converts API response to domain entity.
+  QuickLink toEntity() => QuickLink(
+    id: id.toString(),
+    name: title,
+    url: url,
+    iconName: icon ?? 'link',
+    category: category,
+    sortOrder: position,
+    isActive: isVisible,
+  );
+
+  /// Creates model from domain entity for API requests.
+  factory QuickLinkModel.fromEntity(QuickLink entity) => QuickLinkModel(
+    id: int.tryParse(entity.id) ?? 0,
+    title: entity.name,
+    url: entity.url,
+    icon: entity.iconName,
+    category: entity.category,
+    position: entity.sortOrder,
+    isVisible: entity.isActive,
+  );
+}
+```
+
+**Critical rules for CRUD models:**
+
+1. **Always use generated `toJson()`** - Never write custom JSON methods that selectively include fields. The generated `toJson()` from freezed/json_serializable always includes ALL fields, which is the correct behavior.
+
+2. **Never create custom `toCreateJson()` or similar** - This leads to bugs where fields are silently dropped.
+
+3. **Use `fromEntity()` factory** - Maps domain entity fields to API field names.
+
+### Form Update Pattern
+
+When updating existing entities in forms, **always use `copyWith()`** to preserve existing data:
+
+```dart
+// ✅ Correct - preserves all existing fields
+final updatedLink = existingLink.copyWith(
+  name: _nameController.text.trim(),
+  url: _urlController.text.trim(),
+  category: category.isEmpty ? null : category,
+);
+await actions.update(updatedLink);
+
+// ❌ Wrong - loses existing data not in form
+final newLink = QuickLink(
+  id: existingLink.id,
+  name: _nameController.text.trim(),
+  url: _urlController.text.trim(),
+  // Missing: sortOrder, other fields...
+);
+```
+
+### Datasource Usage
+
+```dart
+// Create - convert entity to model, use toJson()
+Future<QuickLink> createQuickLink(QuickLink link) async {
+  final model = QuickLinkModel.fromEntity(link);
+  final response = await _dio.post<Map<String, dynamic>>(
+    _basePath,
+    data: model.toJson(), // Always use generated toJson()
+  );
+  return QuickLinkModel.fromJson(response.data!).toEntity();
+}
+
+// Update - same pattern
+Future<QuickLink> updateQuickLink(QuickLink link) async {
+  final model = QuickLinkModel.fromEntity(link);
+  final response = await _dio.put<Map<String, dynamic>>(
+    '$_basePath/${link.id}',
+    data: model.toJson(), // Always use generated toJson()
+  );
+  return QuickLinkModel.fromJson(response.data!).toEntity();
+}
+```
+
 ### Presentation Layer (Flutter + Riverpod)
 
 The presentation layer contains UI code and state management.