test(rag_integration): wrap _send_gemini mock return in Result(data=...)

The test_rag_integration test mocks the internal _send_gemini
function to return a raw string. The production code in
app_controller._handle_request_event now does 'if result.ok:'
which fails on raw strings.

Change: mock_provider.return_value = 'Mock AI Response' ->
         mock_provider.return_value = Result(data='Mock AI Response')

Plus add the Result import.

1 test passes (was 1 pre-existing failure).

tests/test_rag_integration.py

@@ -8,6 +8,7 @@ from src.app_controller import AppController
 from src import ai_client
 from src import events
 from src import models
+from src.result_types import Result
 
 @pytest.fixture
 def mock_project():
@@ -74,7 +75,7 @@ def test_rag_integration(mock_project):
  # _send_gemini which is what actually "sends to the provider".
  with patch('src.ai_client.send_result', wraps=ai_client.send_result) as mock_send:
   with patch('src.ai_client._send_gemini') as mock_provider:
-   mock_provider.return_value = "Mock AI Response"
+   mock_provider.return_value = Result(data="Mock AI Response")
    
    # Create a UserRequestEvent as if the user clicked "Gen + Send"
    event = events.UserRequestEvent(