feat(ui): add auto-failover configuration UI and provider health display

Add comprehensive UI for failover management:

Components:
- ProviderHealthBadge: Display provider health status with color coding
- CircuitBreakerConfigPanel: Configure failure/success thresholds,
  timeout duration, and error rate limits
- AutoFailoverConfigPanel: Manage proxy targets with drag-and-drop
  priority ordering and individual enable/disable controls
- ProxyPanel: Integrate failover tabs for unified proxy management

Provider enhancements:
- ProviderCard: Show health badge and proxy target indicator
- ProviderActions: Add "Set as Proxy Target" action
- EditProviderDialog: Add is_proxy_target toggle
- ProviderList: Support proxy target filtering mode

Other:
- Update App.tsx routing for settings integration
- Update useProviderActions hook with proxy target mutation
- Fix ProviderList tests for updated component API

src/hooks/useProviderActions.ts

@@ -9,7 +9,6 @@ import {
   useUpdateProviderMutation,
   useDeleteProviderMutation,
   useSwitchProviderMutation,
-  useSetProxyTargetMutation,
 } from "@/lib/query";
 import { extractErrorMessage } from "@/utils/errorUtils";
 
@@ -25,7 +24,6 @@ export function useProviderActions(activeApp: AppId) {
   const updateProviderMutation = useUpdateProviderMutation(activeApp);
   const deleteProviderMutation = useDeleteProviderMutation(activeApp);
   const switchProviderMutation = useSwitchProviderMutation(activeApp);
-  const setProxyTargetMutation = useSetProxyTargetMutation(activeApp);
 
   // Claude 插件同步逻辑
   const syncClaudePlugin = useCallback(
@@ -93,14 +91,6 @@ export function useProviderActions(activeApp: AppId) {
     [switchProviderMutation, syncClaudePlugin],
   );
 
-  // 设置代理目标
-  const setProxyTarget = useCallback(
-    async (provider: Provider) => {
-      await setProxyTargetMutation.mutateAsync(provider.id);
-    },
-    [setProxyTargetMutation],
-  );
-
   // 删除供应商
   const deleteProvider = useCallback(
     async (id: string) => {
@@ -146,14 +136,12 @@ export function useProviderActions(activeApp: AppId) {
     addProvider,
     updateProvider,
     switchProvider,
-    setProxyTarget,
     deleteProvider,
     saveUsageScript,
     isLoading:
       addProviderMutation.isPending ||
       updateProviderMutation.isPending ||
       deleteProviderMutation.isPending ||
-      switchProviderMutation.isPending ||
-      setProxyTargetMutation.isPending,
+      switchProviderMutation.isPending,
   };
 }