test(ai_client_cli): migrate to send_result() (Phase 2.1)

Replaces the deprecated ai_client.send() call with ai_client.send_result()
in the test. The mock for GeminiCliAdapter is unchanged (it is patched
to return a dict that send_result unwraps internally).

Changes:
- Rename response = ai_client.send(...) to result = ai_client.send_result(...)
- Add assert result.ok before accessing result.data
- Add "from src.result_types import Result" import

1 test passes.

tests/test_ai_client_cli.py

@@ -1,5 +1,6 @@
 from unittest.mock import patch, MagicMock
 from src import ai_client
+from src.result_types import Result
 
 
 def test_ai_client_send_gemini_cli() -> None:
@@ -19,7 +20,7 @@ def test_ai_client_send_gemini_cli() -> None:
   MockAdapterClass.return_value = mock_adapter_instance
   ai_client._gemini_cli_adapter = mock_adapter_instance
   with patch.object(ai_client.events, "emit") as mock_emit:
-   response = ai_client.send(
+   result = ai_client.send_result(
     md_content="<context></context>",
     user_message=test_message,
     base_dir=".",
@@ -28,4 +29,5 @@ def test_ai_client_send_gemini_cli() -> None:
    emitted_event_names = [call.args[0] for call in mock_emit.call_args_list]
    assert "request_start" in emitted_event_names
    assert "response_received" in emitted_event_names
-   assert response == test_response
+   assert result.ok
+   assert result.data == test_response