Fix: Add pagination to admin appointments endpoint

- Added pagination with page/per_page query params
- Fixed N+1 query by using eager-loaded user relationship
- Removed unused _get_user_email helper function
- Updated frontend to handle paginated response
- Regenerated API types

backend/tests/test_booking.py

@@ -716,8 +716,13 @@ class TestAdminViewAppointments:
         
         assert response.status_code == 200
         data = response.json()
-        assert len(data) >= 1
-        assert any(apt["note"] == "Test" for apt in data)
+        # Paginated response
+        assert "records" in data
+        assert "total" in data
+        assert "page" in data
+        assert "per_page" in data
+        assert len(data["records"]) >= 1
+        assert any(apt["note"] == "Test" for apt in data["records"])
 
     @pytest.mark.asyncio
     async def test_regular_user_cannot_view_all_appointments(self, client_factory, regular_user):