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-tauri/src/database/schema.rs

@@ -96,11 +96,9 @@ impl Database {
         // 5. Skills 表
         conn.execute(
             "CREATE TABLE IF NOT EXISTS skills (
-                directory TEXT NOT NULL,
-                app_type TEXT NOT NULL,
+                key TEXT PRIMARY KEY,
                 installed BOOLEAN NOT NULL DEFAULT 0,
-                installed_at INTEGER NOT NULL DEFAULT 0,
-                PRIMARY KEY (directory, app_type)
+                installed_at INTEGER NOT NULL DEFAULT 0
             )",
             [],
         )
@@ -338,6 +336,28 @@ impl Database {
         )
         .map_err(|e| AppError::Database(e.to_string()))?;
 
+        // 15. Circuit Breaker Config 表 (熔断器配置)
+        conn.execute(
+            "CREATE TABLE IF NOT EXISTS circuit_breaker_config (
+                id INTEGER PRIMARY KEY CHECK (id = 1),
+                failure_threshold INTEGER NOT NULL DEFAULT 5,
+                success_threshold INTEGER NOT NULL DEFAULT 2,
+                timeout_seconds INTEGER NOT NULL DEFAULT 60,
+                error_rate_threshold REAL NOT NULL DEFAULT 0.5,
+                min_requests INTEGER NOT NULL DEFAULT 10,
+                updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
+            )",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
+        // 插入默认熔断器配置
+        conn.execute(
+            "INSERT OR IGNORE INTO circuit_breaker_config (id) VALUES (1)",
+            [],
+        )
+        .map_err(|e| AppError::Database(e.to_string()))?;
+
         Ok(())
     }
 
@@ -371,9 +391,7 @@ impl Database {
                         Self::set_user_version(conn, 1)?;
                     }
                     1 => {
-                        log::info!(
-                            "迁移数据库从 v1 到 v2（添加使用统计表和完整字段，重构 skills 表）"
-                        );
+                        log::info!("迁移数据库从 v1 到 v2（添加使用统计表和完整字段）");
                         Self::migrate_v1_to_v2(conn)?;
                         Self::set_user_version(conn, 2)?;
                     }
@@ -462,7 +480,7 @@ impl Database {
         Ok(())
     }
 
-    /// v1 -> v2 迁移：添加使用统计表和完整字段，重构 skills 表
+    /// v1 -> v2 迁移：添加使用统计表和完整字段
     fn migrate_v1_to_v2(conn: &Connection) -> Result<(), AppError> {
         // providers 表字段
         Self::add_column_if_missing(
@@ -558,82 +576,6 @@ impl Database {
             .map_err(|e| AppError::Database(format!("清空模型定价失败: {e}")))?;
         Self::seed_model_pricing(conn)?;
 
-        // 重构 skills 表（添加 app_type 字段）
-        Self::migrate_skills_table(conn)?;
-
-        Ok(())
-    }
-
-    /// 迁移 skills 表：从单 key 主键改为 (directory, app_type) 复合主键
-    fn migrate_skills_table(conn: &Connection) -> Result<(), AppError> {
-        // 检查是否已经是新表结构
-        if Self::has_column(conn, "skills", "app_type")? {
-            log::info!("skills 表已经包含 app_type 字段，跳过迁移");
-            return Ok(());
-        }
-
-        log::info!("开始迁移 skills 表...");
-
-        // 1. 重命名旧表
-        conn.execute("ALTER TABLE skills RENAME TO skills_old", [])
-            .map_err(|e| AppError::Database(format!("重命名旧 skills 表失败: {e}")))?;
-
-        // 2. 创建新表
-        conn.execute(
-            "CREATE TABLE skills (
-                directory TEXT NOT NULL,
-                app_type TEXT NOT NULL,
-                installed BOOLEAN NOT NULL DEFAULT 0,
-                installed_at INTEGER NOT NULL DEFAULT 0,
-                PRIMARY KEY (directory, app_type)
-            )",
-            [],
-        )
-        .map_err(|e| AppError::Database(format!("创建新 skills 表失败: {e}")))?;
-
-        // 3. 迁移数据：解析 key 格式（如 "claude:my-skill" 或 "codex:foo"）
-        //    旧数据如果没有前缀，默认为 claude
-        let mut stmt = conn
-            .prepare("SELECT key, installed, installed_at FROM skills_old")
-            .map_err(|e| AppError::Database(format!("查询旧 skills 数据失败: {e}")))?;
-
-        let old_skills: Vec<(String, bool, i64)> = stmt
-            .query_map([], |row| {
-                Ok((
-                    row.get::<_, String>(0)?,
-                    row.get::<_, bool>(1)?,
-                    row.get::<_, i64>(2)?,
-                ))
-            })
-            .map_err(|e| AppError::Database(format!("读取旧 skills 数据失败: {e}")))?
-            .collect::<Result<Vec<_>, _>>()
-            .map_err(|e| AppError::Database(format!("解析旧 skills 数据失败: {e}")))?;
-
-        let count = old_skills.len();
-
-        for (key, installed, installed_at) in old_skills {
-            // 解析 key: "app:directory" 或 "directory"（默认 claude）
-            let (app_type, directory) = if let Some(idx) = key.find(':') {
-                let (app, dir) = key.split_at(idx);
-                (app.to_string(), dir[1..].to_string()) // 跳过冒号
-            } else {
-                ("claude".to_string(), key.clone())
-            };
-
-            conn.execute(
-                "INSERT INTO skills (directory, app_type, installed, installed_at) VALUES (?1, ?2, ?3, ?4)",
-                rusqlite::params![directory, app_type, installed, installed_at],
-            )
-            .map_err(|e| {
-                AppError::Database(format!("迁移 skill {key} 到新表失败: {e}"))
-            })?;
-        }
-
-        // 4. 删除旧表
-        conn.execute("DROP TABLE skills_old", [])
-            .map_err(|e| AppError::Database(format!("删除旧 skills 表失败: {e}")))?;
-
-        log::info!("skills 表迁移完成，共迁移 {count} 条记录");
         Ok(())
     }