feat: Implement Flutter mobile app MVP

Complete Flutter mobile app structure with:
- All data models (Account, Event, Player, Staff, Convocation, EventDetail, UserInfo)
- ApiService with Dio and Bearer token interceptor
- AuthService with OIDC via flutter_web_auth and deep links
- AuthProvider, ScheduleProvider, EventDetailProvider state management
- LoginScreen, ScheduleScreen with filters, EventDetailScreen
- Reusable widgets: EventCard, FilterDropdown, LoadingIndicator
- main.dart with MultiProvider and auth initialization
- AndroidManifest.xml and Info.plist deep link configuration for myice://callback

Connects to existing FastAPI backend for schedule, events, and auth.

myice_mobile/.gitignore

@@ -0,0 +1,54 @@
+# Flutter/Dart specific
+.dart_tool/
+.packages
+build/
+.pub/
+
+# IDEs
+.idea/
+*.iml
+*.ipr
+*.iws
+*.ctxt
+
+# macOS
+.DS_Store
+
+# Android
+*.apk
+*.ap_
+*.aab
+!/android/app/src/main/AndroidManifest.xml
+
+# iOS
+ios/Pods/
+ios/.symlinks/
+ios/Flutter/Flutter.framework
+ios/Flutter/Flutter.podspec
+
+# Xcode
+xcuserdata/
+*.xcworkspace/
+DerivedData/
+
+# Web
+lib/generated_plugin_registrant.dart
+
+# Windows
+windows/flutter/
+windows/runner/
+
+# Linux
+linux/flutter/
+linux/runner/
+
+# Firebase
+firebase_app_id_file.json
+
+# Coverage
+coverage/
+
+# Temporary files
+*.tmp
+*.swp
+*~