fix: add a one-time alpha recovery tag

[tensornull]

Summary

• authorize only the one-time SemVer recovery tag v0.1.0-alpha.1+recovery.1 for package version 0.1.0a1
• reject the permanently tombstoned v0.1.0-alpha.1 tag and any incremented recovery suffix
• exercise the + tag through version and release-trust tests
• keep Release Please disabled until a separately reviewed and tested last-release-sha bridge establishes the previous-release boundary
• record the recovery decision in the engineering, architecture, release, roadmap, and changelog contracts

Root cause

GitHub permanently reserves the identity of a published immutable release even after an authorized emergency deletion. The corrected 0.1.0a1 commit therefore cannot reuse v0.1.0-alpha.1, although PyPI accepted no distribution from the failed attempt.

Impact

The GitHub recovery release will use valid SemVer build metadata while its wheel, source distribution, and PyPI identity remain exactly 0.1.0a1. Future releases continue to require their ordinary canonical tag spelling.

Verification

• uv sync --locked
• uv run ruff check src tests scripts
• uv run ruff format --check src tests scripts
• uv run pyright
• uv run pytest -m "not live" — 205 passed, 1 deselected
• recovery tag accepted; tombstoned and incremented tags rejected
• uv run python scripts/check_version.py --tag 'v0.1.0-alpha.1+recovery.1' --require-changelog --require-releasable-docs
• uv run python scripts/check_secrets.py
• uv run python scripts/check_workflows.py
• uv build
• uv run twine check dist/*
• uv run python scripts/check_artifacts.py dist/*
• uv run python scripts/check_clean_install.py dist/*
• uv run python scripts/check_repository_independence.py
• uv run python scripts/run_actionlint.py

Independent adversarial review found and then verified fixes for both fail-closed tag selection and the Release Please boundary risk. No blocker remains.