chore: 添加 macOS/Web 平台支持 + 修复编译错误 + 开发环境文档

- 修复 CardTheme → CardThemeData（Flutter 3.41 API 变更）
- 修复 finance_screen 缺少 FormDialog import
- 修复工具栏 Row overflow（添加横向滚动）
- flutter create --platforms=macos,web 生成平台配置
- 添加 docs/dev-setup.md：完整开发环境配置指南
  含 Go/Flutter/Docker 安装、已知 macOS 26 兼容问题及解决方案

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/.gitignore

@@ -0,0 +1,45 @@
+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.build/
+.buildlog/
+.history
+.svn/
+.swiftpm/
+migrate_working_dir/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
+.dart_tool/
+.flutter-plugins-dependencies
+.pub-cache/
+.pub/
+/build/
+/coverage/
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Android Studio will place build artifacts here
+/android/app/debug
+/android/app/profile
+/android/app/release