fix(release): tolerate workflow bytecode cache

[pentaxis93]

Summary

• Fixes release-cut so the documented release ceremony can run after prior release-check invocations have imported release_lib.
• Keeps the clean-tree guard strict for genuine untracked artifacts.
• Records that Release-ceremony test asserts stale methodology version — full suite fails on main #315 is satisfied by the current manifest-version contract once the full suite is green.

Changes

• Remove generated scripts/__pycache__/release_lib.*.pyc files immediately before release-cut checks git status --short.
• Add regression coverage for the documented release-check metadata + release-check release + release-cut path.
• Add guard coverage proving an unrelated untracked file still fails the clean-tree pre-check.

GitHub Issue(s)

Closes #311
Closes #315

Test plan

• python -m unittest tests.test_release_ceremony.ReleaseRepositoryContractTests.test_manifest_declares_current_methodology_version
• python -m unittest tests.test_release_ceremony.ReleaseCeremonyTests
• python -m unittest discover -s tests