feat(desktop): 后端健康监控韧性 + onboarding 修复 + 全局代理 UI

- useCheckBackend 重写：60s 总超时取代 while(true) 死轮询，订阅 Tauri
  backend-ready/terminated/startup-timeout 事件，裸 fetch 探测避免
  启动期 toast 叠堆
- Tauri lib.rs：spawn 后 HTTP 探针轮询 /api/sys_check 拿 200 才算就绪
  （之前 TCP connect 会被孤儿进程误判）；RunEvent::Exit 钩子退出前
  kill sidecar，修孤儿进程占端口；restart 前发 backend-restarting
  让前端忽略主动 kill 引发的 terminated
- BackendInitDialog：失败态展示原因 + 最近 stderr + 重启/复制日志按钮
- StartupBanner：收到 restarted/ready 自动清「已退出」横幅
- BackendHealthIndicator：修 /api/api/sys_health 双前缀 404
- Onboarding：step1 后端连通改自动重试 + 事件触发 + 手动按钮；step2
  撞预置供应商名时改为更新已存在供应商；errText 统一错误文案
- 全局代理 UI：下载配置页新增代理卡片（services/proxy.ts + ProxyConfig）
- request.ts 加 suppressToast 配置位，预期失败不弹全局红 toast
- NoteForm/taskStore：捕获就绪门禁错误，引导去音频转写配置页下载
- providerCard：整行可点切换（之前只有 icon 区域响应）
- Monitor 页 Whisper 卡显示模型本地下载状态
- tauri/api 升级对齐 2.11，修 vite build 版本不匹配

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

BillNote_frontend/pnpm-lock.yaml

@@ -54,11 +54,11 @@ importers:
         specifier: ^4.1.3
         version: 4.2.2(vite@6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.32.0)(yaml@2.8.3))
       '@tauri-apps/api':
-        specifier: ^2.10.1
-        version: 2.10.1
+        specifier: ^2.11.0
+        version: 2.11.0
       '@tauri-apps/plugin-shell':
-        specifier: ~2.2.2
-        version: 2.2.2
+        specifier: ~2.3.5
+        version: 2.3.5
       '@uiw/react-markdown-preview':
         specifier: ^5.1.3
         version: 5.1.5(@types/react@19.2.14)(react-dom@19.2.4(react@19.2.4))(react@19.2.4)
@@ -1590,8 +1590,8 @@ packages:
     peerDependencies:
       vite: ^5.2.0 || ^6 || ^7 || ^8
 
-  '@tauri-apps/api@2.10.1':
-    resolution: {integrity: sha512-hKL/jWf293UDSUN09rR69hrToyIXBb8CjGaWC7gfinvnQrBVvnLr08FeFi38gxtugAVyVcTa5/FD/Xnkb1siBw==}
+  '@tauri-apps/api@2.11.0':
+    resolution: {integrity: sha512-7CinYODhky9lmO23xHnUFv0Xt43fbtWMyxZcLcRBlFkcgXKuEirBvHpmtJ89YMhyeGcq20Wuc47Fa4XjyniywA==}
 
   '@tauri-apps/cli-darwin-arm64@2.10.1':
     resolution: {integrity: sha512-Z2OjCXiZ+fbYZy7PmP3WRnOpM9+Fy+oonKDEmUE6MwN4IGaYqgceTjwHucc/kEEYZos5GICve35f7ZiizgqEnQ==}
@@ -1669,8 +1669,8 @@ packages:
     engines: {node: '>= 10'}
     hasBin: true
 
-  '@tauri-apps/plugin-shell@2.2.2':
-    resolution: {integrity: sha512-fg9XKWfzRQsN8p+Zrk82WeHvXFvGVnG0/mTlujQdLWNnO5cM6WD9qCrHbFytScVS+WhmRAkuypQPcxeKKl3VBg==}
+  '@tauri-apps/plugin-shell@2.3.5':
+    resolution: {integrity: sha512-jewtULhiQ7lI7+owCKAjc8tYLJr92U16bPOeAa472LHJdgaibLP83NcfAF2e+wkEcA53FxKQAZ7byDzs2eeizg==}
 
   '@types/babel__core@7.20.5':
     resolution: {integrity: sha512-qoQprZvz5wQFJwMDqeseRXWv3rqMvhgpbXFfVyWhbx9X47POIA6i/+dXefEmZKoAgOaTdaIgNSMqMIU61yRyzA==}
@@ -6463,7 +6463,7 @@ snapshots:
       tailwindcss: 4.2.2
       vite: 6.4.1(@types/node@22.19.15)(jiti@2.6.1)(lightningcss@1.32.0)(yaml@2.8.3)
 
-  '@tauri-apps/api@2.10.1': {}
+  '@tauri-apps/api@2.11.0': {}
 
   '@tauri-apps/cli-darwin-arm64@2.10.1':
     optional: true
@@ -6512,9 +6512,9 @@ snapshots:
       '@tauri-apps/cli-win32-ia32-msvc': 2.10.1
       '@tauri-apps/cli-win32-x64-msvc': 2.10.1
 
-  '@tauri-apps/plugin-shell@2.2.2':
+  '@tauri-apps/plugin-shell@2.3.5':
     dependencies:
-      '@tauri-apps/api': 2.10.1
+      '@tauri-apps/api': 2.11.0
 
   '@types/babel__core@7.20.5':
     dependencies: