refactor: 抽取高危功能页共享脚手架与传输层日志

诊断：功能票 / 解锁歌曲 / 收藏品 / 旅行伙伴 / 数值修改 / 一键跑图 /
万花筒 / 高危 hub 这些页面各自抄了一份同样的脚手架——冷却计时器、_Step
枚举、自动退登开关、卡片/提示/进度卡；TitleApiService.getUserPreview 还
重复实现了整套传输层；服务层有 37 处裸 print 会把 token / JSESSIONID
打进日志。

- 新增共享原语，7 个功能页切换到：
  * widgets/cooldown_mixin.dart  CooldownMixin（登录后冷却倒计时）
  * widgets/step_progress.dart   RiskStep + StepProgressCard
  * widgets/app_card.dart        AppCard / SectionTitle / AutoLogoutToggle
  * widgets/app_notice.dart      AppNotice + context.showSnack
- TitleApiService: getUserPreview 收敛进通用 _callApi；新增 fromHolder()
  工厂与 config getter，消除散落的 isConfigured + config!
- 传输层 print -> ApiLog（仅 debug 输出），删除全部 avoid_print 忽略
- UserAllPayloadBuilder 新增 placeholderMusicData()（原 5 处重复）
- LoginPage 从 main.dart 抽到 pages/login_page.dart，入口只留 main + MyApp
- 更新 README / CLAUDE.md 目录结构与已过时的 web/依赖说明

验证：flutter analyze 0 issue（含 info）；flutter test 96/96 通过。
纯结构重构，行为保持不变；仅有意统一了功能票 / 音乐风险 / hub 的
卡片与步骤视觉样式。

净删除约 2176 行重复代码。

CLAUDE.md

@@ -5,12 +5,9 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 ## Build & Development Commands
 
 ```bash
-# Run the app (launches on connected device or browser)
+# Run the app (launches on connected device)
 flutter run
 
-# Run specifically for web (primary target)
-flutter run -d chrome
-
 # Run analyzer
 flutter analyze
 
@@ -20,8 +17,12 @@ flutter test
 # Run a single test file
 flutter test test/widget_test.dart
 
-# Build for web
-flutter build web
+# Build release artifacts
+flutter build apk --release          # Android
+flutter build windows --release      # Windows
+flutter build macos --release        # macOS
+flutter build linux --release        # Linux
+flutter build ios --release --no-codesign   # iOS（无证书时只验证可编译）
 
 # Check for outdated dependencies
 flutter pub outdated
@@ -32,31 +33,55 @@ flutter pub upgrade --major-versions
 
 ## Architecture
 
-This is a Flutter app (targeting mobile native) that serves as a QR-code-based login client for the maimai DX arcade game network.
+This is a Flutter app (Android / iOS / Windows / macOS / Linux) that serves as a QR-code-based
+login client for the maimai DX arcade game network.
 
 ### Code Layout
 
 ```
 lib/
-├── main.dart                # App entry point, LoginPage widget (the entire UI)
+├── main.dart                # 入口：main() + MyApp（MaterialApp）
+├── pages/
+│   ├── login_page.dart      # 登录页（QR 粘贴 / 图片识别）
+│   ├── home_page.dart       # 主页骨架（底部导航 + 各 tab）
+│   ├── settings_page.dart   # Title Server / 机器参数配置
+│   └── ...                  # 各功能页（ticket / best50 / 风险操作等）
+├── widgets/
+│   ├── cooldown_mixin.dart  # CooldownMixin：登录后冷却倒计时
+│   ├── step_progress.dart   # RiskStep + StepProgressCard
+│   ├── app_card.dart        # AppCard / SectionTitle / AutoLogoutToggle
+│   ├── app_notice.dart      # AppNotice + context.showSnack
+│   └── best50_poster.dart   # B50 成绩图
 └── services/
-    ├── api_service.dart     # API client for game server auth
-    ├── qr_service.dart      # Platform-agnostic QR decode interface (conditional import)
-    ├── qr_service_native.dart  # Native stub — QR decode is NOT implemented on mobile/desktop
-    └── qr_service_web.dart  # Web QR decode via jsQR (loaded in web/index.html via CDN)
+    ├── api_service.dart     # Aime 登录 API 客户端
+    ├── title_api_service.dart # 游戏服务器传输层（加解密 / 会话 / 各 Api）
+    ├── user_all_payload_builder.dart # UpsertUserAll 组装与各补丁
+    ├── api_log.dart         # 传输层调试日志（仅 debug）
+    └── ...
 ```
 
 ### Key Design Decisions
 
-- **Single-widget app**: The entire app is currently one `LoginPage` widget in `main.dart`. There is no routing — the login result shows an `AlertDialog`.
-- **Conditional imports for platform code**: `qr_service.dart` uses the `if (dart.library.html)` syntax to import `qr_service_web.dart` on web and `qr_service_native.dart` everywhere else. Native QR scanning returns `null` (not implemented).
-- **Web is the primary target**: jsQR is loaded via CDN `<script>` tag in `web/index.html`. The web QR decoder draws the image onto a `<canvas>`, extracts `ImageData`, and calls `jsQR()` via `dart:js`.
-- **Auth flow**: `ApiService.login()` takes a QR code token (last 64 chars), builds a SHA-256 key from `chipID + JST-timestamp + chimeSalt`, and POSTs JSON to `http://ai.sys-allnet.cn/wc_aime/api/get_data`. A successful response has `errorID: 0` and returns `userID` + `token`.
-- **Timestamp is JST (UTC+9)**: The API key derivation uses Japan Standard Time, formatted as `yyMMddHHmmss`.
+- **Risk-flow scaffolding is shared**: the feature pages (ticket / unlock music / collectibles /
+  travel partner / number patch / map traverse / kaleidx / risk hub) all use `CooldownMixin`,
+  `RiskStep`, `StepProgressCard`, `AppCard`, `AppNotice` and `AutoLogoutToggle` instead of
+  copy-pasting the same timer / step / banner / card code. Keep new pages on these primitives.
+- **QR decoding is native-only**: `services/qr_service.dart` calls the
+  `dev.naominet.ichino/qr_scanner` MethodChannel, implemented by Android's `MainActivity` and
+  iOS's `SceneDelegate`. Desktop has no handler, so image-based QR scanning is mobile-only.
+- **Auth flow**: `ApiService.login()` takes a QR code token (last 64 chars), builds a SHA-256 key
+  from `chipID + JST-timestamp + chimeSalt`, and POSTs JSON to the configured Aime URL. A successful
+  response has `errorID: 0` and returns `userID` + `token`.
+- **Title server transport**: `TitleApiService` derives the URL path from
+  `MD5(apiName + salt + obfuscateParam)`, JSON → ZLib → AES-CBC encodes/decodes, and keeps the
+  `JSESSIONID` cookie. `getUserPreview` and every other API go through the same `_callApi` helper.
+- **Timestamp is JST (UTC+9)** for Aime key derivation, formatted `yyMMddHHmmss`.
 
 ### Notable Dependencies
 
 - `http` — API calls
-- `crypto` — SHA-256 for API key derivation
+- `crypto` — MD5 URL hash + SHA-256 Aime key
+- `pointycastle` / `archive` — AES-CBC + ZLib for the title-server wire format
 - `image_picker` — picking QR images from the device gallery
-- `google_fonts` — custom fonts (currently unused in code)
+- `shared_preferences` — persisted `TitleServerConfig`
+- `share_plus` — exporting the B50 PNG