fix: ignore Python bytecode during release validation

[pixincreate]

Summary

• ignore Python bytecode caches generated by the Action validation scripts
• require the bytecode ignore rules in the distribution validator to prevent regression

Root cause

The v2.0.0 GitHub Release preflight ran the Python validator, which imported scenario modules and generated untracked __pycache__/*.pyc files. The subsequent strict cargo package --locked check rejected the dirty checkout.

Verification

• regression reproduced before the fix: ERROR: Python bytecode caches must be ignored
• python3 scripts/action_validation/validate.py
• python3 -m py_compile scripts/action_validation/*.py
• cargo package --locked
• git diff --check
• Oracle release-safety audit: PASS