Filter detected sellers from conversations

tests/web/conversations-route.test.ts

@@ -226,6 +226,28 @@ describe('conversations route', () => {
     expect(await response.json()).toEqual([{ ...conversation, hasReceivedImages: true }]);
   });
 
+  it('marks conversations with a durable seller detection', async () => {
+    const conversation = {
+      username: 'seller', roomName: 'seller', roomId: 'room-seller',
+      lastMessageTime: 1, lastMessageSnippet: 'my page', isFromUs: false, unread: true,
+    };
+    const context = {
+      logger: { error: vi.fn() },
+      services: {
+        chat: { getCachedConversations: vi.fn().mockResolvedValue([conversation]) },
+        conversationState: {
+          get: vi.fn(() => ({ sellerDetected: true })),
+        },
+      },
+    } as unknown as WebContext;
+    const app = express().use('/api', createConversationsRouter(context));
+
+    const response = await request(app, '/api/conversations');
+
+    expect(response.status).toBe(200);
+    expect(await response.json()).toEqual([{ ...conversation, sellerDetected: true }]);
+  });
+
   it('serves conversation details without starting a delta sync', async () => {
     const conversation = {
       username: 'alice',