fix: update group sync tests to use proper Response mocks

tests/unit/services/group-sync.test.ts

@@ -15,18 +15,22 @@ describe('GroupSyncService', () => {
     db.exec('DELETE FROM sqlite_sequence WHERE name="groups"');
     GroupSyncService['lastSyncAttempt'] = 0;
     
-    // Setup mock fetch
-    fetchMock = mock(async () => ({
-      ok: true,
-      json: async () => ({
-        status: 'success',
-        response: [
-          { id: 'group1', subject: 'Group 1', linkedParent: 'test-community' },
-          { id: 'group2', subject: 'Group 2', linkedParent: 'other-community' },
-          { id: 'group3', subject: 'Group 3' } // No linkedParent
-        ]
-      })
-    }));
+    // Setup mock fetch to return proper Response object
+    fetchMock = mock(async () => {
+      const groups = [
+        { id: 'group1', subject: 'Group 1', linkedParent: 'test-community' },
+        { id: 'group2', subject: 'Group 2', linkedParent: 'other-community' },
+        { id: 'group3', subject: 'Group 3' } // No linkedParent
+      ];
+      return {
+        ok: true,
+        status: 200,
+        statusText: 'OK',
+        headers: new Headers({'Content-Type': 'application/json'}),
+        text: async () => JSON.stringify(groups),
+        json: async () => groups
+      };
+    });
     globalThis.fetch = fetchMock;
 
     // Setup env vars
@@ -139,7 +143,11 @@ describe('GroupSyncService', () => {
       
       globalThis.fetch = mock(async () => ({
         ok: false,
-        statusText: 'Not Found'
+        status: 404,
+        statusText: 'Not Found',
+        headers: new Headers(),
+        text: async () => 'Not Found',
+        json: async () => ({ error: 'Not Found' })
       }));
       
       await expect(GroupSyncService.syncGroups()).rejects.toThrow('API request failed: Not Found');