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/components/providers/HealthStatusIndicator.tsx

@@ -1,6 +1,7 @@
 import React from "react";
 import { cn } from "@/lib/utils";
 import type { HealthStatus } from "@/lib/api/model-test";
+import { useTranslation } from "react-i18next";
 
 interface HealthStatusIndicatorProps {
   status: HealthStatus;
@@ -11,17 +12,20 @@ interface HealthStatusIndicatorProps {
 const statusConfig = {
   operational: {
     color: "bg-emerald-500",
-    label: "正常",
+    labelKey: "health.operational",
+    labelFallback: "正常",
     textColor: "text-emerald-600 dark:text-emerald-400",
   },
   degraded: {
     color: "bg-yellow-500",
-    label: "降级",
+    labelKey: "health.degraded",
+    labelFallback: "降级",
     textColor: "text-yellow-600 dark:text-yellow-400",
   },
   failed: {
     color: "bg-red-500",
-    label: "失败",
+    labelKey: "health.failed",
+    labelFallback: "失败",
     textColor: "text-red-600 dark:text-red-400",
   },
 };
@@ -31,13 +35,15 @@ export const HealthStatusIndicator: React.FC<HealthStatusIndicatorProps> = ({
   responseTimeMs,
   className,
 }) => {
+  const { t } = useTranslation();
   const config = statusConfig[status];
+  const label = t(config.labelKey, { defaultValue: config.labelFallback });
 
   return (
     <div className={cn("flex items-center gap-2", className)}>
       <div className={cn("w-2 h-2 rounded-full", config.color)} />
       <span className={cn("text-xs font-medium", config.textColor)}>
-        {config.label}
+        {label}
         {responseTimeMs !== undefined && ` (${responseTimeMs}ms)`}
       </span>
     </div>