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/hooks/useProxyStatus.ts

@@ -51,7 +51,8 @@ export function useProxyStatus() {
     },
     onError: (error: Error) => {
       const detail =
-        extractErrorMessage(error) || t("common.unknown", { defaultValue: "未知错误" });
+        extractErrorMessage(error) ||
+        t("common.unknown", { defaultValue: "未知错误" });
       toast.error(
         t("proxy.server.startFailed", {
           defaultValue: `启动代理服务失败: ${detail}`,
@@ -77,7 +78,8 @@ export function useProxyStatus() {
     },
     onError: (error: Error) => {
       const detail =
-        extractErrorMessage(error) || t("common.unknown", { defaultValue: "未知错误" });
+        extractErrorMessage(error) ||
+        t("common.unknown", { defaultValue: "未知错误" });
       toast.error(
         t("proxy.stopWithRestoreFailed", {
           defaultValue: `停止失败: ${detail}`,
@@ -114,7 +116,8 @@ export function useProxyStatus() {
     },
     onError: (error: Error) => {
       const detail =
-        extractErrorMessage(error) || t("common.unknown", { defaultValue: "未知错误" });
+        extractErrorMessage(error) ||
+        t("common.unknown", { defaultValue: "未知错误" });
       toast.error(
         t("proxy.takeover.failed", {
           defaultValue: `操作失败: ${detail}`,
@@ -137,7 +140,8 @@ export function useProxyStatus() {
     },
     onError: (error: Error) => {
       const detail =
-        extractErrorMessage(error) || t("common.unknown", { defaultValue: "未知错误" });
+        extractErrorMessage(error) ||
+        t("common.unknown", { defaultValue: "未知错误" });
       toast.error(
         t("proxy.switchFailed", {
           error: detail,