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/themes.dart

@@ -0,0 +1,43 @@
+import 'package:flutter/material.dart';
+import 'package:habo/constants.dart';
+
+class HaboTheme {
+  static ThemeData lightTheme() {
+    return ThemeData(
+      brightness: Brightness.light,
+      primarySwatch: Colors.green,
+      colorScheme: ColorScheme.fromSeed(
+        seedColor: HaboColors.primary,
+        brightness: Brightness.light,
+      ),
+      scaffoldBackgroundColor: HaboColors.lightBg,
+      useMaterial3: true,
+    );
+  }
+
+  static ThemeData darkTheme() {
+    return ThemeData(
+      brightness: Brightness.dark,
+      primarySwatch: Colors.green,
+      colorScheme: ColorScheme.fromSeed(
+        seedColor: HaboColors.primary,
+        brightness: Brightness.dark,
+      ),
+      scaffoldBackgroundColor: HaboColors.darkBg,
+      useMaterial3: true,
+    );
+  }
+
+  static ThemeData oledTheme() {
+    return ThemeData(
+      brightness: Brightness.dark,
+      primarySwatch: Colors.green,
+      colorScheme: ColorScheme.fromSeed(
+        seedColor: HaboColors.primary,
+        brightness: Brightness.dark,
+      ),
+      scaffoldBackgroundColor: Colors.black,
+      useMaterial3: true,
+    );
+  }
+}