Use single-underscore discard for awaited results

CodeQL flagged the named `_result`/`_captured_permission_request`
discards as unused locals after the prior commit. Switch to the
single-underscore convention, which CodeQL's py/unused-local-variable
rule and ruff F841 both treat as an intentional discard.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: stephentoub

python/e2e/test_pending_work_resume_e2e.py

@@ -159,7 +159,7 @@ def original_tool_handler(args):
                 await session1.send(
                     "Use resume_permission_tool with value 'alpha', then reply with the result."
                 )
-                _captured_permission_request = await captured_request
+                _ = await captured_request
                 permission_event = await permission_event_task
 
                 # Force-stop the suspended client without releasing the in-flight

python/e2e/test_rpc_mcp_and_skills_e2e.py

@@ -61,7 +61,7 @@ def _assert_skill(skills, skill_name: str, *, enabled: bool):
 
 async def _assert_failure(awaitable, expected: str) -> None:
     with pytest.raises(Exception) as excinfo:
-        _result = await awaitable
+        _ = await awaitable
     assert expected.lower() in str(excinfo.value).lower()
 
 

python/e2e/test_rpc_session_state_e2e.py

@@ -43,7 +43,7 @@ def _conversation_messages(events) -> list[tuple[str, str]]:
 
 async def _assert_implemented_failure(awaitable, method: str) -> None:
     with pytest.raises(Exception) as excinfo:
-        _result = await awaitable
+        _ = await awaitable
     assert f"Unhandled method {method}".lower() not in str(excinfo.value).lower()
 
 

python/e2e/test_rpc_tasks_and_handlers_e2e.py

@@ -32,7 +32,7 @@
 
 async def _assert_implemented_failure(awaitable, method: str) -> None:
     with pytest.raises(Exception) as excinfo:
-        _result = await awaitable
+        _ = await awaitable
     assert f"Unhandled method {method}".lower() not in str(excinfo.value).lower()