feat(failover): add auto-failover master switch with proxy integration (#427)

* feat(failover): add auto-failover master switch with proxy integration

- Add persistent auto_failover_enabled setting in database
- Add get/set_auto_failover_enabled commands
- Provider router respects master switch state
- Proxy shutdown automatically disables failover
- Enabling failover auto-starts proxy server
- Optimistic updates for failover queue toggle

* feat(proxy): persist proxy takeover state across app restarts

- Add proxy_takeover_{app_type} settings for per-app state tracking
- Restore proxy takeover state automatically on app startup
- Preserve state on normal exit, clear on manual stop
- Add stop_with_restore_keep_state method for graceful shutdown

* fix(proxy): set takeover state for all apps in start_with_takeover

src/components/mcp/UnifiedMcpPanel.tsx

@@ -237,9 +237,7 @@ const UnifiedMcpListItem: React.FC<UnifiedMcpListItemProps> = ({
       {/* 左侧：服务器信息 */}
       <div className="flex-1 min-w-0">
         <div className="flex items-center gap-2 mb-1">
-          <h3 className="font-medium text-foreground">
-            {name}
-          </h3>
+          <h3 className="font-medium text-foreground">{name}</h3>
           {docsUrl && (
             <Button
               type="button"