[datlechin]

Change

• Delete scripts/ci/check-changelog.py, its tests, and its steps in Repo Hygiene and PR title.
• Repo Hygiene keeps towncrier build --draft for apple and linux. It refuses an unknown type or a non-numeric PR number.
• PR title refuses an edit to apple/CHANGELOG.md or linux/CHANGELOG.md unless the title starts with chore(release). It reads the merge commit's diff to its first parent, the PR's own change.
• version.py check refuses a lead on a patch, a lead over 6 lines, and a lead line starting with # or - .
• Nothing else from _new_section_problems is kept. Its only other check, notes.py cannot find ## [X], cannot fire once the heading matched.
• No longer CI checks: the 120-character limit, the ending period, the PR-number fragment name, release PRs touching only the changelog. The first two stay as writing guidance.
• .claude/rules/changelog.md is 5 facts. ci.md, apple/RELEASING.md and linux/docs/releasing.md no longer say the checker runs.

Verified

• New lead tests in test_version.py fail with the rules removed.
• Repo Hygiene's tooling tests, actionlint, shellcheck, both towncrier drafts and verify.sh agent-docs pass locally.

Not in this PR

• Root AGENTS.md still lists a changelog check in scripts/ci; the AGENTS.md PR owns that line.
• Linux lead rules are guidance only now; the Linux release shows the whole section.