test: stub has_hook in transform_tool_result hook tests

CI slice 3 caught that tests/test_transform_tool_result_hook.py monkeypatches
invoke_hook but not has_hook, so the new has_hook("transform_tool_result")
gate skipped the emit and the transform never ran. Stub has_hook=True in the
shared _run_handle_function_call helper whenever a custom invoke_hook is
supplied (the test intends hooks to fire). The no-hook-registered test keeps
the real has_hook=False path — that's the gate's intended behavior.

tests/test_transform_tool_result_hook.py

@@ -36,6 +36,10 @@ def _run_handle_function_call(
     if invoke_hook is not _UNSET:
         # Patch the symbol actually imported inside handle_function_call.
         monkeypatch.setattr("hermes_cli.plugins.invoke_hook", invoke_hook)
+        # Supplying a custom invoke_hook means the test expects hooks to
+        # fire — make has_hook agree so the has_hook gate doesn't skip the
+        # post_tool_call / transform_tool_result emit paths.
+        monkeypatch.setattr("hermes_cli.plugins.has_hook", lambda name: True)
 
     return model_tools.handle_function_call(
         tool_name,