i18n: complete internationalization for v3.8+ features

- Add health status translations (operational, degraded, failed, circuitOpen)
- Add proxy panel translations (serviceAddress, stats, stopped state)
- Add usage filter translations (appType, statusCode, searchPlaceholder)
- Add providerIcon click hints (clickToChange, clickToSelect)
- Add config load error translations for main.tsx
- Complete Japanese proxy section (failoverQueue, autoFailover)
- Fix date/time locale in usage charts and tables
- Use t() function in all hardcoded UI strings

src/hooks/useProxyStatus.ts

@@ -50,7 +50,8 @@ export function useProxyStatus() {
       queryClient.invalidateQueries({ queryKey: ["proxyStatus"] });
     },
     onError: (error: Error) => {
-      const detail = extractErrorMessage(error) || "未知错误";
+      const detail =
+        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}`,
@@ -75,7 +76,8 @@ export function useProxyStatus() {
       queryClient.invalidateQueries({ queryKey: ["providerHealth"] });
     },
     onError: (error: Error) => {
-      const detail = extractErrorMessage(error) || "未知错误";
+      const detail =
+        extractErrorMessage(error) || t("common.unknown", { defaultValue: "未知错误" });
       toast.error(
         t("proxy.stopWithRestoreFailed", {
           defaultValue: `停止失败: ${detail}`,
@@ -111,7 +113,8 @@ export function useProxyStatus() {
       queryClient.invalidateQueries({ queryKey: ["proxyTakeoverStatus"] });
     },
     onError: (error: Error) => {
-      const detail = extractErrorMessage(error) || "未知错误";
+      const detail =
+        extractErrorMessage(error) || t("common.unknown", { defaultValue: "未知错误" });
       toast.error(
         t("proxy.takeover.failed", {
           defaultValue: `操作失败: ${detail}`,
@@ -133,8 +136,14 @@ export function useProxyStatus() {
       queryClient.invalidateQueries({ queryKey: ["proxyStatus"] });
     },
     onError: (error: Error) => {
-      const detail = extractErrorMessage(error) || "未知错误";
-      toast.error(`切换失败: ${detail}`);
+      const detail =
+        extractErrorMessage(error) || t("common.unknown", { defaultValue: "未知错误" });
+      toast.error(
+        t("proxy.switchFailed", {
+          error: detail,
+          defaultValue: `切换失败: ${detail}`,
+        }),
+      );
     },
   });