fix(data): 增加全局保存失败保护

apps/web/lib/server-data.ts

@@ -37,6 +37,12 @@ const serverDataCache = new Map<ServerDataKey, {
 }>();
 const serverDataLoadPromises = new Map<ServerDataKey, Promise<unknown | null>>();
 export const SERVER_DATA_CACHE_MS = 30_000;
+export const SERVER_DATA_SAVE_ERROR_EVENT = 'ftb:server-data-save-error';
+
+export type ServerDataSaveErrorDetail = {
+  key: ServerDataKey;
+  message: string;
+};
 
 type LoadServerDataOptions = {
   force?: boolean;
@@ -54,6 +60,24 @@ export class ServerDataConflictError<T = unknown> extends Error {
   }
 }
 
+function getServerDataSaveErrorMessage(error: unknown) {
+  if (error instanceof ServerDataConflictError) return '数据已被其他用户更新，请刷新后重试';
+  if (error instanceof Error && error.message) return error.message;
+  return '保存失败，请检查网络或 API 服务';
+}
+
+function notifyServerDataSaveFailure(key: ServerDataKey, error: unknown) {
+  if (typeof window === 'undefined') return;
+  window.dispatchEvent(
+    new CustomEvent(SERVER_DATA_SAVE_ERROR_EVENT, {
+      detail: {
+        key,
+        message: getServerDataSaveErrorMessage(error),
+      },
+    }),
+  );
+}
+
 export async function loadServerData<T>(
   key: ServerDataKey,
   options: LoadServerDataOptions = {},
@@ -107,12 +131,15 @@ export async function saveServerData<T>(key: ServerDataKey, value: T): Promise<v
       error.status === 409 &&
       isServerDataConflictBody<T>(error.body, key)
     ) {
-      throw new ServerDataConflictError(
+      const conflict = new ServerDataConflictError(
         error.body.key,
         error.body.currentValue,
         error.body.currentVersion,
       );
+      notifyServerDataSaveFailure(key, conflict);
+      throw conflict;
     }
+    notifyServerDataSaveFailure(key, error);
     throw error;
   }
 }