[g-seo]

Summary

Clarify deadlock failures when the workflow thread ID is unavailable, and verify stack trace capture for unsandboxed workflows.

Behavior

• Add (no thread ID available) to the deadlock message when the workflow instance provides no thread ID.
• Extend the unsandboxed deadlock test to assert that the workflow-task failure recorded in history contains the blocked workflow's stack frame.
• Add focused coverage for the missing-thread-ID diagnostic.

Validation

• PYTHONPATH=. .venv/bin/python -m pytest tests/worker/test_workflow.py -k workflow_deadlock -q — 5 passed, 243 deselected.
• Editable Rust bridge build — passed.
• uv run ruff check --select I and uv run ruff format --check — passed.
• uv run pyright, uv run mypy --namespace-packages --check-untyped-defs ., and uv run basedpyright — passed.
• uv run pydocstyle --ignore-decorators=overload, cargo fmt --check, and git diff --check — passed.

The full test suite and CI were not run. Poe the Poet was unavailable, so its underlying test, formatting, and lint commands were run directly.

Compatibility

No public API or workflow execution behavior changes. The deadlock message changes only when no thread ID is available; interruption and eviction behavior remain unchanged.

Closes #722

[CLAassistant]

All committers have signed the CLA.