feat: initial commit - Habo habit tracking app

- Complete MVP with Repository Pattern, SQLite storage
- Provider + ChangeNotifier state management
- Navigation 2.0 with deep link support
- Habit CRUD with twoDayRule, notifications, categories
- Backup/Restore via JSON
- Statistics with streak tracking
- Material You theme support
- Biometric lock support
- Desktop widget support
- 27 languages i18n structure
- Comprehensive test suite (87/89 passing)

lib/model/category.dart

@@ -0,0 +1,31 @@
+class Category {
+  int? id;
+  String title;
+  int iconCodePoint;
+  String? fontFamily;
+
+  Category({
+    this.id,
+    this.title = '',
+    this.iconCodePoint = 0,
+    this.fontFamily,
+  });
+
+  Map<String, dynamic> toJson() {
+    return {
+      'id': id,
+      'title': title,
+      'iconCodePoint': iconCodePoint,
+      'fontFamily': fontFamily,
+    };
+  }
+
+  factory Category.fromJson(Map<String, dynamic> json) {
+    return Category(
+      id: json['id'] as int?,
+      title: json['title'] as String? ?? '',
+      iconCodePoint: json['iconCodePoint'] as int? ?? 0,
+      fontFamily: json['fontFamily'] as String?,
+    );
+  }
+}