Push async submit, Chinese 422 field labels, hide server CSV export.

Return sync/files immediately with background runner; show loc_zh in validation errors; remove servers toolbar CSV export button.

frontend/src/utils/apiError.ts

@@ -1,22 +1,15 @@
 import { ApiError } from '@/api'
+import { formatValidationDetail } from '@/utils/validationErrorFormat'
 
 /** Turn FastAPI error bodies into a human-readable string. */
 export function formatApiError(e: unknown, fallback: string): string {
-  let msg = fallback
   if (e instanceof ApiError) {
     const d = (e as ApiError & { detail?: unknown }).detail ?? e.message
-    if (typeof d === 'string') msg = d
-    else if (Array.isArray(d)) {
-      msg = d.map((x: { msg?: string; loc?: unknown[] }) => {
-        const part = x?.msg || JSON.stringify(x)
-        const loc = Array.isArray(x.loc) ? x.loc.filter((p) => p !== 'body').join('.') : ''
-        return loc ? `${loc}: ${part}` : part
-      }).join('; ')
-    } else if (d && typeof d === 'object') msg = JSON.stringify(d)
-    else msg = e.message || fallback
-  } else if (e instanceof Error) {
-    msg = e.message || fallback
+    return formatValidationDetail(d, e.message || fallback)
   }
-  msg = msg.trim()
-  return msg || fallback
+  if (e instanceof Error) {
+    const msg = e.message.trim()
+    return msg || fallback
+  }
+  return fallback
 }