fix: classify Release Please push state

[tensornull]

What changed

• Limit automatic Release Please pushes to canonical package-version changes and classify unchanged published versions without mutation.
• Reject non-patch, manifest-drifted, or stale-tag push state before invoking Release Please.
• Preserve Release Please-generated CHANGELOG bytes by excluding it from Prettier while retaining semantic and PR-body equality gates.

Why

Run 30439065922 exposed historical v0.1.0 being mistaken for same-run recovery, and candidate CI run 30439337121 exposed Prettier rewriting the action-owned CHANGELOG.

Verification

• npm run format:check
• npm run lint
• npm run typecheck
• npm test (373 tests)
• npm run actionlint (1.7.12)
• npm run check:self-contained (exact committed tree)
• npm run verify through all gates except its duplicate self-contained invocation before commit; the committed self-contained run then passed
• git diff --check