test(orchestrator_pm_history): mock send_result not send (Phase 2.15, pre-empts Phase 1.2 regression)

Phase 1.2 migrated src/orchestrator_pm.py:86 to send_result(). The
test_generate_tracks_with_history test mocked src.ai_client.send,
which would break once Phase 1.2 was applied. (Confirmed: test failed
after Phase 1.2 commit.)

Changes:
- Replace @patch(src.ai_client.send) with @patch(src.ai_client.send_result)
- Rename mock_send to mock_send_result
- Wrap mock return_value with Result(data="[]")
- Add "from src.result_types import Result" import

All 3 tests in test_orchestrator_pm_history.py pass.

tests/test_orchestrator_pm_history.py

@@ -4,6 +4,7 @@ import shutil
 import json
 from pathlib import Path
 from src import orchestrator_pm
+from src.result_types import Result
 
 class TestOrchestratorPMHistory(unittest.TestCase):
  def setUp(self) -> None:
@@ -58,13 +59,13 @@ class TestOrchestratorPMHistory(unittest.TestCase):
   self.assertIn("No overview available", summary)
 
  @patch('src.orchestrator_pm.summarize.build_summary_markdown')
- @patch('src.ai_client.send')
- def test_generate_tracks_with_history(self, mock_send: MagicMock, mock_summarize: MagicMock) -> None:
+ @patch('src.ai_client.send_result')
+ def test_generate_tracks_with_history(self, mock_send_result: MagicMock, mock_summarize: MagicMock) -> None:
   mock_summarize.return_value = "REPO_MAP"
-  mock_send.return_value = "[]"
+  mock_send_result.return_value = Result(data="[]")
   history_summary = "PAST_HISTORY_SUMMARY"
   orchestrator_pm.generate_tracks("req", {}, [], history_summary=history_summary)
-  args, kwargs = mock_send.call_args
+  args, kwargs = mock_send_result.call_args
   self.assertIn(history_summary, kwargs['user_message'])
   self.assertIn("### TRACK HISTORY:", kwargs['user_message'])