refactor(proxy): remove is_proxy_target in favor of failover_queue

- Remove `is_proxy_target` field from Provider struct (Rust & TypeScript)
- Remove related DAO methods: get_proxy_target_provider, set_proxy_target
- Remove deprecated Tauri commands: get_proxy_targets, set_proxy_target
- Add `is_available()` method to CircuitBreaker for availability checks
  without consuming HalfOpen probe permits (used in select_providers)
- Keep `allow_request()` for actual request gating with permit tracking
- Update stream_check to use failover_queue instead of is_proxy_target
- Clean up commented-out reset circuit breaker button in ProviderActions
- Remove unused useProxyTargets and useSetProxyTarget hooks

tests/components/SettingsDialog.test.tsx

@@ -19,6 +19,23 @@ vi.mock("react-i18next", () => ({
   useTranslation: () => ({ t: tMock }),
 }));
 
+vi.mock("@/hooks/useProxyStatus", () => ({
+  useProxyStatus: () => ({
+    status: null,
+    isLoading: false,
+    isRunning: false,
+    isTakeoverActive: false,
+    startWithTakeover: vi.fn(),
+    stopWithRestore: vi.fn(),
+    switchProxyProvider: vi.fn(),
+    checkRunning: vi.fn(),
+    checkTakeoverActive: vi.fn(),
+    isStarting: false,
+    isStopping: false,
+    isPending: false,
+  }),
+}));
+
 interface SettingsMock {
   settings: any;
   isLoading: boolean;
@@ -288,6 +305,7 @@ describe("SettingsPage Component", () => {
     });
 
     fireEvent.click(screen.getByText("settings.tabAdvanced"));
+    fireEvent.click(screen.getByText("数据管理"));
 
     // 有文件时，点击导入按钮执行 importConfig
     fireEvent.click(
@@ -363,6 +381,7 @@ describe("SettingsPage Component", () => {
     await waitFor(() => {
       expect(toastSuccessMock).toHaveBeenCalledWith(
         "settings.devModeRestartHint",
+        expect.objectContaining({ closeButton: true }),
       );
     });
   });
@@ -393,6 +412,7 @@ describe("SettingsPage Component", () => {
     render(<SettingsPage open={true} onOpenChange={vi.fn()} />);
 
     fireEvent.click(screen.getByText("settings.tabAdvanced"));
+    fireEvent.click(screen.getByText("配置文件目录"));
 
     fireEvent.click(screen.getByText("browse-directory"));
     expect(settingsMock.browseDirectory).toHaveBeenCalledWith("claude");

tests/hooks/useImportExport.extra.test.tsx

@@ -120,6 +120,7 @@ describe("useImportExport Hook (edge cases)", () => {
     expect(exportConfigMock).toHaveBeenCalledWith("/exports/config.json");
     expect(toastSuccessMock).toHaveBeenCalledWith(
       expect.stringContaining("/final/config.json"),
+      expect.objectContaining({ closeButton: true }),
     );
   });
 });

tests/hooks/useImportExport.test.tsx

@@ -180,6 +180,7 @@ describe("useImportExport Hook", () => {
     expect(exportConfigMock).toHaveBeenCalledWith("/export.json");
     expect(toastSuccessMock).toHaveBeenCalledWith(
       expect.stringContaining("/backup/export.json"),
+      expect.objectContaining({ closeButton: true }),
     );
   });
 

tests/integration/SettingsDialog.test.tsx

@@ -150,6 +150,7 @@ describe("SettingsPage integration", () => {
       expect(screen.getByText("language:zh")).toBeInTheDocument(),
     );
     fireEvent.click(screen.getByText("settings.tabAdvanced"));
+    fireEvent.click(screen.getByText("配置文件目录"));
     const appInput = await screen.findByPlaceholderText(
       "settings.browsePlaceholderApp",
     );
@@ -165,6 +166,7 @@ describe("SettingsPage integration", () => {
     );
 
     fireEvent.click(screen.getByText("settings.tabAdvanced"));
+    fireEvent.click(screen.getByText("数据管理"));
     fireEvent.click(screen.getByText("settings.selectConfigFile"));
     await waitFor(() =>
       expect(screen.getByTestId("selected-file").textContent).toContain(
@@ -188,6 +190,7 @@ describe("SettingsPage integration", () => {
     );
 
     fireEvent.click(screen.getByText("settings.tabAdvanced"));
+    fireEvent.click(screen.getByText("配置文件目录"));
     const appInput = await screen.findByPlaceholderText(
       "settings.browsePlaceholderApp",
     );
@@ -214,6 +217,7 @@ describe("SettingsPage integration", () => {
     );
 
     fireEvent.click(screen.getByText("settings.tabAdvanced"));
+    fireEvent.click(screen.getByText("配置文件目录"));
 
     const browseButtons = screen.getAllByTitle("settings.browseDirectory");
     const resetButtons = screen.getAllByTitle("settings.resetDefault");
@@ -253,6 +257,7 @@ describe("SettingsPage integration", () => {
       expect(screen.getByText("language:zh")).toBeInTheDocument(),
     );
     fireEvent.click(screen.getByText("settings.tabAdvanced"));
+    fireEvent.click(screen.getByText("数据管理"));
 
     server.use(
       http.post("http://tauri.local/save_file_dialog", () =>

tests/msw/handlers.ts

@@ -236,4 +236,64 @@ export const handlers = [
   http.post(`${TAURI_ENDPOINT}/sync_current_providers_live`, () =>
     success({ success: true }),
   ),
+
+  // Proxy status (for SettingsPage / ProxyPanel hooks)
+  http.post(`${TAURI_ENDPOINT}/get_proxy_status`, () =>
+    success({
+      running: false,
+      address: "127.0.0.1",
+      port: 0,
+      active_connections: 0,
+      total_requests: 0,
+      success_requests: 0,
+      failed_requests: 0,
+      success_rate: 0,
+      uptime_seconds: 0,
+      current_provider: null,
+      current_provider_id: null,
+      last_request_at: null,
+      last_error: null,
+      failover_count: 0,
+      active_targets: [],
+    }),
+  ),
+
+  http.post(`${TAURI_ENDPOINT}/is_live_takeover_active`, () => success(false)),
+
+  // Failover / circuit breaker defaults
+  http.post(`${TAURI_ENDPOINT}/get_failover_queue`, () => success([])),
+  http.post(`${TAURI_ENDPOINT}/get_available_providers_for_failover`, () =>
+    success([]),
+  ),
+  http.post(`${TAURI_ENDPOINT}/add_to_failover_queue`, () => success(true)),
+  http.post(`${TAURI_ENDPOINT}/remove_from_failover_queue`, () => success(true)),
+  http.post(`${TAURI_ENDPOINT}/reorder_failover_queue`, () => success(true)),
+  http.post(`${TAURI_ENDPOINT}/set_failover_item_enabled`, () => success(true)),
+
+  http.post(`${TAURI_ENDPOINT}/get_circuit_breaker_config`, () =>
+    success({
+      failureThreshold: 3,
+      successThreshold: 2,
+      timeoutSeconds: 60,
+      errorRateThreshold: 50,
+      minRequests: 5,
+    }),
+  ),
+  http.post(`${TAURI_ENDPOINT}/update_circuit_breaker_config`, () =>
+    success(true),
+  ),
+  http.post(`${TAURI_ENDPOINT}/get_provider_health`, () =>
+    success({
+      provider_id: "mock-provider",
+      app_type: "claude",
+      is_healthy: true,
+      consecutive_failures: 0,
+      last_success_at: null,
+      last_failure_at: null,
+      last_error: null,
+      updated_at: new Date().toISOString(),
+    }),
+  ),
+  http.post(`${TAURI_ENDPOINT}/reset_circuit_breaker`, () => success(true)),
+  http.post(`${TAURI_ENDPOINT}/get_circuit_breaker_stats`, () => success(null)),
 ];