fix(tests): correct test_sanitize_agent_error_stderr_and_exc assertion

The test expected the exception class to be hidden when stderr is provided,
but the implementation always uses the exc type as the tag. Fix the
assertion to match actual (correct) behavior: ValueError is in the tag,
stderr is the body. Also add a check that we don't fall back to the
generic "workspace logs" form.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

workspace/tests/test_executor_helpers.py

@@ -763,6 +763,7 @@ def test_sanitize_agent_error_stderr_and_exc():
     out = sanitize_agent_error(exc=err, stderr="rate limit exceeded")
     assert "ValueError" in out  # exc class IS the tag when stderr is provided
     assert "rate limit exceeded" in out
+    assert "workspace logs" not in out  # stderr form, not the generic form
 
 
 def test_sanitize_agent_error_stderr_empty_string():