feat(groups): include member profile fields in chat members API

tests/test_chat_message_flow.py

@@ -774,6 +774,34 @@ async def test_group_admin_can_edit_chat_profile(client, db_session):
     assert body["description"] == "Updated by admin"
 
 
+async def test_chat_members_endpoint_returns_user_profile_fields(client, db_session):
+    owner = await _create_verified_user(client, db_session, "members_owner@example.com", "members_owner", "strongpass123")
+    member = await _create_verified_user(client, db_session, "members_user@example.com", "members_user", "strongpass123")
+
+    me_member = await client.get("/api/v1/auth/me", headers={"Authorization": f"Bearer {member['access_token']}"})
+    member_id = me_member.json()["id"]
+
+    create_group = await client.post(
+        "/api/v1/chats",
+        headers={"Authorization": f"Bearer {owner['access_token']}"},
+        json={"type": ChatType.GROUP.value, "title": "Members profile group", "member_ids": [member_id]},
+    )
+    assert create_group.status_code == 200
+    chat_id = create_group.json()["id"]
+
+    members_response = await client.get(
+        f"/api/v1/chats/{chat_id}/members",
+        headers={"Authorization": f"Bearer {owner['access_token']}"},
+    )
+    assert members_response.status_code == 200
+    rows = members_response.json()
+    member_row = next((item for item in rows if item["user_id"] == member_id), None)
+    assert member_row is not None
+    assert member_row["username"] == "members_user"
+    assert "name" in member_row
+    assert "avatar_url" in member_row
+
+
 async def test_group_admin_cannot_change_member_roles(client, db_session):
     owner = await _create_verified_user(client, db_session, "roles_owner@example.com", "roles_owner", "strongpass123")
     admin_user = await _create_verified_user(client, db_session, "roles_admin@example.com", "roles_admin", "strongpass123")