feat(provider): 增加 Claude Code 适配器、高级配置能力与 OAuth 账号类型统一解析

- 新增 Claude Code provider adapter (context, envelope, plugin, constants)
- 扩展 provider admin 路由，支持 Claude Code 高级配置 (CRUD)
- 统一 OAuth 账号类型解析逻辑，前后端对齐
- 重构 BatchAssignModelsDialog / ModelMappingDialog，简化组件逻辑
- handler 基类增强: request_builder 支持 Claude Code 信封格式
- CLI stream/sync mixin 适配 Claude Code 流式与同步模式
- 扩展 candidate builder / failover / scheduler 对 Claude Code 的支持
- 前端增加请求时间线可视化 (HorizontalRequestTimeline)
- 补充 Claude Code envelope / runtime controls / distributed sessions 等测试

Closes #183
Closes #185

Co-Authored-By: AAEE86 <ppk0227@hotmail.com>

frontend/src/layouts/MainLayout.vue

@@ -357,6 +357,7 @@ import {
   Gauge,
   Layers,
   FolderTree,
+  Database,
   Box,
   LogOut,
   SunMoon,
@@ -554,6 +555,7 @@ const navigation = computed(() => {
       items: [
         { name: '用户管理', href: '/admin/users', icon: Users },
         { name: '提供商', href: '/admin/providers', icon: FolderTree },
+        { name: '号池管理', href: '/admin/pool', icon: Database },
         { name: '模型管理', href: '/admin/models', icon: Layers },
         { name: '独立密钥', href: '/admin/keys', icon: Key },
         { name: '异步任务', href: '/admin/async-tasks', icon: Zap },