fix: resolve pytest warnings for test_workspace functions

Fixed pytest warnings where context manager functions were incorrectly
identified as test functions because their names started with 'test_'.

Changes:
- Renamed test_workspace() to workspace_context() in test_utils.py
- Updated import in test_issue_145_production_error_handler.py
- Updated usage in temp_workspace fixture

This eliminates 2 warnings:
  PytestReturnNotNoneWarning: Test functions should return None,
  but test_workspace returned <class 'contextlib._GeneratorContextManager'>

Test Results:
- Before: 1,160 passed, 0 failed, 38 skipped, 2 warnings
- After: 1,158 passed, 0 failed, 38 skipped, 0 warnings

Note: Test count decreased by 2 because the misnamed functions are no
longer being collected as tests (which is correct behavior).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

tests/test_utils.py

@@ -38,7 +38,7 @@ def create_test_workspace(prefix: str = "test") -> Path:
 
 
 @contextmanager
-def test_workspace(prefix: str = "test"):
+def workspace_context(prefix: str = "test"):
     """Context manager for test workspace that auto-cleans up.
 
     Args: