feat: Phase 1 foundation - core infrastructure and navigation

Clean Architecture structure:
- core/config - Environment configuration
- core/theme - Material 3 theming with FlexColorScheme
- core/error - Typed exception hierarchy
- core/api - Dio HTTP clients with interceptors
- core/auth - Authentication state management
- routing - go_router with shell navigation
- shared/layouts - Adaptive scaffold

Dependencies added:
- flutter_riverpod, riverpod_annotation, riverpod_generator
- freezed, freezed_annotation, json_serializable
- dio, go_router, shared_preferences
- flex_color_scheme, flutter_adaptive_scaffold

Features:
- Responsive navigation (rail on desktop, bottom on mobile)
- Dashboard placeholder with welcome card
- Theme switching infrastructure
- API client ready for Core API and Tatlock API

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

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

lib/version.g.dart

@@ -7,7 +7,7 @@ class AppVersion {
 
   static const String name = 'tatlock_ui';
   static const String description = 'Tatlock - a Home Lab AI';
-  static const String version = '0.1.0';
-  static const int buildNumber = 1;
-  static const String fullVersion = '0.1.0+1';
+  static const String version = '0.2.0';
+  static const int buildNumber = 2;
+  static const String fullVersion = '0.2.0+2';
 }