ci: prevent changelog formatter drift

[molvqingtai]

Summary

• format the current v2.0.1 CHANGELOG.md output so CI does not mutate the base checkout
• format only CHANGELOG.md during semantic-release prepare before the release commit

Validation

• pnpm run format
• pnpm run lint (0 errors; existing warnings only)
• git diff --exit-code
• pnpm run check

Fixes the common linter failure seen on PR #81 and PR #83 without modifying either documentation branch.

[molvqingtai]

Superseded by the same CI repair now appended to the owning requirement PR #81 (a52f219). Closing unmerged to preserve the one-requirement/one-PR workflow.