Feat/auto failover (#367)

* feat(db): add circuit breaker config table and provider proxy target APIs

Add database support for auto-failover feature:

- Add circuit_breaker_config table for storing failover thresholds
- Add get/update_circuit_breaker_config methods in proxy DAO
- Add reset_provider_health method for manual recovery
- Add set_proxy_target and get_proxy_targets methods in providers DAO
  for managing multi-provider failover configuration

* feat(proxy): implement circuit breaker and provider router for auto-failover

Add core failover logic:

- CircuitBreaker: Tracks provider health with three states:
  - Closed: Normal operation, requests pass through
  - Open: Circuit broken after consecutive failures, skip provider
  - HalfOpen: Testing recovery with limited requests
- ProviderRouter: Routes requests across multiple providers with:
  - Health tracking and automatic failover
  - Configurable failure/success thresholds
  - Auto-disable proxy target after reaching failure threshold
  - Support for manual circuit breaker reset
- Export new types in proxy module

* feat(proxy): add failover Tauri commands and integrate with forwarder

Expose failover functionality to frontend:

- Add Tauri commands: get_proxy_targets, set_proxy_target,
  get_provider_health, reset_circuit_breaker,
  get/update_circuit_breaker_config, get_circuit_breaker_stats
- Register all new commands in lib.rs invoke handler
- Update forwarder with improved error handling and logging
- Integrate ProviderRouter with proxy server startup
- Add provider health tracking in request handlers

* feat(frontend): add failover API layer and TanStack Query hooks

Add frontend data layer for failover management:

- Add failover.ts API: Tauri invoke wrappers for all failover commands
- Add failover.ts query hooks: TanStack Query mutations and queries
  - useProxyTargets, useProviderHealth queries
  - useSetProxyTarget, useResetCircuitBreaker mutations
  - useCircuitBreakerConfig query and mutation
- Update queries.ts with provider health query key
- Update mutations.ts to invalidate health on provider changes
- Add CircuitBreakerConfig and ProviderHealth types

* 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

* fix(usage): stabilize date range to prevent infinite re-renders

* feat(backend): add tool version check command

Add get_tool_versions command to check local and latest versions of
Claude, Codex, and Gemini CLI tools:

- Detect local installed versions via command line execution
- Fetch latest versions from npm registry (Claude, Gemini)
  and GitHub releases API (Codex)
- Return comprehensive version info including error details
  for uninstalled tools
- Register command in Tauri invoke handler

* style(ui): format accordion component code style

Apply consistent code formatting to accordion component:
- Convert double quotes to semicolons at line endings
- Adjust indentation to 2-space standard
- Align with project code style conventions

* refactor(providers): update provider card styling to use theme tokens

Replace hardcoded color classes with semantic design tokens:
- Use bg-card, border-border, text-card-foreground instead of glass-card
- Replace gray/white color literals with muted/foreground tokens
- Change proxy target indicator color from purple to green
- Improve hover states with border-border-active
- Ensure consistent dark mode support via CSS variables

* refactor(proxy): simplify auto-failover config panel structure

Restructure AutoFailoverConfigPanel for better integration:
- Remove internal Card wrapper and expansion toggle (now handled by parent)
- Extract enabled state to props for external control
- Simplify loading state display
- Clean up redundant CardHeader/CardContent wrappers
- ProxyPanel: reduce complexity by delegating to parent components

* feat(settings): enhance settings page with accordion layout and tool versions

Major settings page improvements:

AboutSection:
- Add local tool version detection (Claude, Codex, Gemini)
- Display installed vs latest version comparison with visual indicators
- Show update availability badges and environment check cards

SettingsPage:
- Reorganize advanced settings into collapsible accordion sections
- Add proxy control panel with inline status toggle
- Integrate auto-failover configuration with accordion UI
- Add database and cost calculation config sections

DirectorySettings & WindowSettings:
- Minor styling adjustments for consistency

settings.ts API:
- Add getToolVersions() wrapper for new backend command

* refactor(usage): restructure usage dashboard components

Comprehensive usage statistics panel refactoring:

UsageDashboard:
- Reorganize layout with improved section headers
- Add better loading states and empty state handling

ModelStatsTable & ProviderStatsTable:
- Minor styling updates for consistency

ModelTestConfigPanel & PricingConfigPanel:
- Simplify component structure
- Remove redundant Card wrappers
- Improve form field organization

RequestLogTable:
- Enhance table layout with better column sizing
- Improve pagination controls

UsageSummaryCards:
- Update card styling with semantic tokens
- Better responsive grid layout

UsageTrendChart:
- Refine chart container styling
- Improve legend and tooltip display

* chore(deps): add accordion and animation dependencies

Package updates:
- Add @radix-ui/react-accordion for collapsible sections
- Add cmdk for command palette support
- Add framer-motion for enhanced animations

Tailwind config:
- Add accordion-up/accordion-down animations
- Update darkMode config to support both selector and class
- Reorganize color and keyframe definitions for clarity

* style(app): update header and app switcher styling

App.tsx:
- Replace glass-header with explicit bg-background/80 backdrop-blur
- Update navigation button container to use bg-muted

AppSwitcher:
- Replace hardcoded gray colors with semantic muted/foreground tokens
- Ensure consistent dark mode support via CSS variables
- Add group class for better hover state transitions

src/components/proxy/CircuitBreakerConfigPanel.tsx

@@ -0,0 +1,208 @@
+import {
+  useCircuitBreakerConfig,
+  useUpdateCircuitBreakerConfig,
+} from "@/lib/query/failover";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import { Button } from "@/components/ui/button";
+import { useState, useEffect } from "react";
+import { toast } from "sonner";
+
+/**
+ * 熔断器配置面板
+ * 允许用户调整熔断器参数
+ */
+export function CircuitBreakerConfigPanel() {
+  const { data: config, isLoading } = useCircuitBreakerConfig();
+  const updateConfig = useUpdateCircuitBreakerConfig();
+
+  const [formData, setFormData] = useState({
+    failureThreshold: 5,
+    successThreshold: 2,
+    timeoutSeconds: 60,
+    errorRateThreshold: 0.5,
+    minRequests: 10,
+  });
+
+  // 当配置加载完成时更新表单数据
+  useEffect(() => {
+    if (config) {
+      setFormData(config);
+    }
+  }, [config]);
+
+  const handleSave = async () => {
+    try {
+      await updateConfig.mutateAsync(formData);
+      toast.success("熔断器配置已保存");
+    } catch (error) {
+      toast.error("保存失败: " + String(error));
+    }
+  };
+
+  const handleReset = () => {
+    if (config) {
+      setFormData(config);
+    }
+  };
+
+  if (isLoading) {
+    return <div className="text-sm text-muted-foreground">加载中...</div>;
+  }
+
+  return (
+    <div className="space-y-6">
+      <div>
+        <h3 className="text-lg font-semibold">熔断器配置</h3>
+        <p className="text-sm text-muted-foreground mt-1">
+          调整熔断器参数以控制故障检测和恢复行为
+        </p>
+      </div>
+
+      <div className="h-px bg-border my-4" />
+
+      <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
+        {/* 失败阈值 */}
+        <div className="space-y-2">
+          <Label htmlFor="failureThreshold">失败阈值</Label>
+          <Input
+            id="failureThreshold"
+            type="number"
+            min="1"
+            max="20"
+            value={formData.failureThreshold}
+            onChange={(e) =>
+              setFormData({
+                ...formData,
+                failureThreshold: parseInt(e.target.value) || 5,
+              })
+            }
+          />
+          <p className="text-xs text-muted-foreground">
+            连续失败多少次后打开熔断器
+          </p>
+        </div>
+
+        {/* 超时时间 */}
+        <div className="space-y-2">
+          <Label htmlFor="timeoutSeconds">超时时间（秒）</Label>
+          <Input
+            id="timeoutSeconds"
+            type="number"
+            min="10"
+            max="300"
+            value={formData.timeoutSeconds}
+            onChange={(e) =>
+              setFormData({
+                ...formData,
+                timeoutSeconds: parseInt(e.target.value) || 60,
+              })
+            }
+          />
+          <p className="text-xs text-muted-foreground">
+            熔断器打开后多久尝试恢复（半开状态）
+          </p>
+        </div>
+
+        {/* 成功阈值 */}
+        <div className="space-y-2">
+          <Label htmlFor="successThreshold">成功阈值</Label>
+          <Input
+            id="successThreshold"
+            type="number"
+            min="1"
+            max="10"
+            value={formData.successThreshold}
+            onChange={(e) =>
+              setFormData({
+                ...formData,
+                successThreshold: parseInt(e.target.value) || 2,
+              })
+            }
+          />
+          <p className="text-xs text-muted-foreground">
+            半开状态下成功多少次后关闭熔断器
+          </p>
+        </div>
+
+        {/* 错误率阈值 */}
+        <div className="space-y-2">
+          <Label htmlFor="errorRateThreshold">错误率阈值 (%)</Label>
+          <Input
+            id="errorRateThreshold"
+            type="number"
+            min="0"
+            max="100"
+            step="5"
+            value={Math.round(formData.errorRateThreshold * 100)}
+            onChange={(e) =>
+              setFormData({
+                ...formData,
+                errorRateThreshold: (parseInt(e.target.value) || 50) / 100,
+              })
+            }
+          />
+          <p className="text-xs text-muted-foreground">
+            错误率超过此值时打开熔断器
+          </p>
+        </div>
+
+        {/* 最小请求数 */}
+        <div className="space-y-2">
+          <Label htmlFor="minRequests">最小请求数</Label>
+          <Input
+            id="minRequests"
+            type="number"
+            min="5"
+            max="100"
+            value={formData.minRequests}
+            onChange={(e) =>
+              setFormData({
+                ...formData,
+                minRequests: parseInt(e.target.value) || 10,
+              })
+            }
+          />
+          <p className="text-xs text-muted-foreground">
+            计算错误率前的最小请求数
+          </p>
+        </div>
+      </div>
+
+      <div className="flex gap-3">
+        <Button onClick={handleSave} disabled={updateConfig.isPending}>
+          {updateConfig.isPending ? "保存中..." : "保存配置"}
+        </Button>
+        <Button
+          variant="outline"
+          onClick={handleReset}
+          disabled={updateConfig.isPending}
+        >
+          重置
+        </Button>
+      </div>
+
+      {/* 说明信息 */}
+      <div className="p-4 bg-muted/50 rounded-lg space-y-2 text-sm">
+        <h4 className="font-medium">配置说明</h4>
+        <ul className="space-y-1 text-muted-foreground">
+          <li>
+            • <strong>失败阈值</strong>：连续失败达到此次数时，熔断器打开
+          </li>
+          <li>
+            • <strong>超时时间</strong>：熔断器打开后，等待此时间后尝试半开
+          </li>
+          <li>
+            • <strong>成功阈值</strong>：半开状态下，成功达到此次数时关闭熔断器
+          </li>
+          <li>
+            • <strong>错误率阈值</strong>：错误率超过此值时，熔断器打开
+          </li>
+          <li>
+            • <strong>最小请求数</strong>：只有请求数达到此值后才计算错误率
+          </li>
+        </ul>
+      </div>
+    </div>
+  );
+}