feat: Modernisation UI/UX et configuration Flutter multi-plateforme

Phase 1 - Corrections Critiques:
- Fixed memory leaks dans music_provider.dart (stream subscriptions)
- Fixed race conditions dans search_provider.dart (stale results)
- Fixed token refresh errors dans api_service.dart
- Improved error handling avec messages utilisateur
- Changed API URL to HTTPS by default

Phase 2 - Améliorations UX Desktop:
- Ajouté cursor pointers sur tous les éléments cliquables
- Implémenté hover states avec effets néon glow (200ms transitions)
- Créé skeleton loading states avec shimmer animation
- Ajouté widgets: ClickableWrapper, ErrorDisplay, SkeletonLoading
- Enhanced visual feedback pour desktop users

Phase 3 - Configuration Flutter:
- Configuré Android (Gradle 8.1.0, Kotlin 1.9.0, minSdk 21, targetSdk 34)
- Créé launcher icons cyberpunk néon (5 densités)
- Configuré Windows desktop (structure complète)
- Activé Linux desktop support
- Ajouté package équatable pour entités de domaine
- Corrigé imports (colors.dart, auth_provider.dart)
- Fixed Dio API compatibility (RequestOptions)

Documentation:
- STYLE_GUIDE.md: Guide complet (100+ pages)
- DESIGN_IMPLEMENTATION_GUIDE.md: Implémentation Flutter
- BUILD_STATUS.md: Status builds + troubleshooting
- QUICKSTART_BUILDS.md: Guide rapide
- BUILD_INDEX.md: Index documentation
- PHASE_1_CORRECTIONS.md: Corrections Phase 1
- PHASE_2_UX_IMPROVEMENTS.md: Améliorations Phase 2
- PR_REVIEW_SUMMARY.md: Revue code complète
- CODE_ANALYSIS_AND_PRIORITIES.md: Analyse code

Scripts & Builds:
- BUILD_ALL.sh: Script automatisé builds multi-plateforme
- builds/: Structure avec README par plateforme
- design-system/: Système de design complet

Backend:
- Ajouté streaming HTTP Range pour audio progressif
- Enhanced YouTube service avec métadonnées complètes
- Improved error handling et validation

Generated with [Claude Code](https://claude.com/claude-code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

frontend/linux/flutter/ephemeral/generated_config.cmake

@@ -0,0 +1,21 @@
+# Generated code do not commit.
+file(TO_CMAKE_PATH "/opt/flutter" FLUTTER_ROOT)
+file(TO_CMAKE_PATH "/opt/audiOhm/frontend" PROJECT_DIR)
+
+set(FLUTTER_VERSION "0.1.0+1" PARENT_SCOPE)
+set(FLUTTER_VERSION_MAJOR 0 PARENT_SCOPE)
+set(FLUTTER_VERSION_MINOR 1 PARENT_SCOPE)
+set(FLUTTER_VERSION_PATCH 0 PARENT_SCOPE)
+set(FLUTTER_VERSION_BUILD 1 PARENT_SCOPE)
+
+# Environment variables to pass to tool_backend.sh
+list(APPEND FLUTTER_TOOL_ENVIRONMENT
+  "FLUTTER_ROOT=/opt/flutter"
+  "PROJECT_DIR=/opt/audiOhm/frontend"
+  "DART_DEFINES=RkxVVFRFUl9WRVJTSU9OPTMuMzguNw==,RkxVVFRFUl9DSEFOTkVMPXN0YWJsZQ==,RkxVVFRFUl9HSVRfVVJMPWh0dHBzOi8vZ2l0aHViLmNvbS9mbHV0dGVyL2ZsdXR0ZXIuZ2l0,RkxVVFRFUl9GUkFNRVdPUktfUkVWSVNJT049M2I2MmVmYzJhMw==,RkxVVFRFUl9FTkdJTkVfUkVWSVNJT049NzhmYzMwMTJlNA==,RkxVVFRFUl9EQVJUX1ZFUlNJT049My4xMC43"
+  "DART_OBFUSCATION=false"
+  "TRACK_WIDGET_CREATION=true"
+  "TREE_SHAKE_ICONS=true"
+  "PACKAGE_CONFIG=/opt/audiOhm/frontend/.dart_tool/package_config.json"
+  "FLUTTER_TARGET=lib/main.dart"
+)