fix(data): 增加全局保存失败保护

apps/web/lib/server-data.test.ts

@@ -1,7 +1,14 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
 
-import { loadServerData, saveServerData, ServerDataConflictError } from './server-data';
+import { __resetApiAvailabilityForTests } from './api';
+import {
+  loadServerData,
+  saveServerData,
+  ServerDataConflictError,
+  SERVER_DATA_SAVE_ERROR_EVENT,
+  type ServerDataSaveErrorDetail,
+} from './server-data';
 
 type MockResponse = {
   status: number;
@@ -172,3 +179,55 @@ test('server data reuses a fresh cached load for repeated AppData reads', async
     globalThis.fetch = originalFetch;
   }
 });
+
+test('server data save failures dispatch a browser-visible failure event', async () => {
+  const originalFetch = globalThis.fetch;
+  const originalWindowDescriptor = Object.getOwnPropertyDescriptor(globalThis, 'window');
+  const events: Array<CustomEvent<ServerDataSaveErrorDetail>> = [];
+  __resetApiAvailabilityForTests();
+
+  Object.defineProperty(globalThis, 'window', {
+    configurable: true,
+    value: {
+      dispatchEvent: (event: Event) => {
+        events.push(event as CustomEvent<ServerDataSaveErrorDetail>);
+        return true;
+      },
+    },
+  });
+
+  globalThis.fetch = (async (input: RequestInfo | URL, init?: RequestInit) => {
+    const url = String(input);
+    if (url.endsWith('/config/ai')) {
+      return new Response(JSON.stringify({}), {
+        status: 200,
+        headers: { 'Content-Type': 'application/json' },
+      });
+    }
+    if (url.endsWith('/data/requirements') && init?.method === 'PUT') {
+      return new Response(JSON.stringify({ message: 'offline' }), {
+        status: 500,
+        headers: { 'Content-Type': 'application/json' },
+      });
+    }
+    throw new Error(`Unexpected fetch ${init?.method ?? 'GET'} ${url}`);
+  }) as typeof fetch;
+
+  try {
+    await assert.rejects(() => saveServerData('requirements', []), /offline/);
+    assert.equal(events.length, 1);
+    assert.equal(events[0].type, SERVER_DATA_SAVE_ERROR_EVENT);
+    assert.deepEqual(events[0].detail, {
+      key: 'requirements',
+      message: 'offline',
+    });
+  } finally {
+    globalThis.fetch = originalFetch;
+    __resetApiAvailabilityForTests();
+    if (originalWindowDescriptor) {
+      Object.defineProperty(globalThis, 'window', originalWindowDescriptor);
+    } else {
+      Reflect.deleteProperty(globalThis, 'window');
+    }
+  }
+});