feat: validate npm publish version and tag inputs

[cafitac]

Summary

• add a release guard module that validates version consistency across package.json, pyproject.toml, and src/ai_crawler/__init__.py
• validate tag-triggered npm publishes against the expected npm-v<version> tag before the workflow reaches publish
• document the tag-based release flow in the README and cover the guard with unit tests plus module smoke checks

Testing

• uv run --extra dev pytest tests/unit/test_npm_publish_guard.py -v
• uv run --extra dev python -m ai_crawler.release.npm_publish --event-name workflow_dispatch --ref-name main
• uv run --extra dev python -m ai_crawler.release.npm_publish --event-name push --ref-name npm-v0.1.1
• bash scripts/check-python.sh
• bash scripts/verify-ai-harness.sh