fix(workflow): fail when run outputs are missing

[liamnwhite1]

Summary

Make workflow runs fail when an executed step does not produce all expected valid outputs.

Related issues

• Closes pytest_examples can sometimes pass even when example case fails to complete #139

Details

This fixes a bug where example tests could pass even when a workflow case failed to complete. Component.run_component() previously printed a warning if an execute stage finished but the expected output files were missing or invalid. Because no exception was raised, pytest and CI could still report success.

The fix changes that post-run validation path to raise a RuntimeError after listing the expected output files. A regression test covers an execute stage that returns successfully but leaves its declared output missing.

Impact

Risk level: Low.

This changes failure behavior for workflows with declared output requirements: missing or invalid outputs after execution now fail loudly instead of logging a warning. That should make example tests and CI catch incomplete runs reliably.

Testing strategy

Environment:

• Local repo .venv
• Python 3.12.10
• pytest 9.0.2

Commands run:

• .venv/bin/python -m pytest tests/test_workflow_context.py
• .venv/bin/python -m pytest tests/test_workflow_context.py tests/test_component_output_paths.py
• .venv/bin/python -m pytest
• git diff --check

Note: uv was not available in this shell, so testing used the repo .venv. External example CI jobs were not run locally because they require the external application/container environment.

Checklist

• Architecture/docs impact considered. Updated ARCHITECTURE.md, developer docs,
  and/or ADRs where needed.