ci: tweak changeset validation skill details

Author: seratch

.codex/skills/changeset-validation/references/validation-prompt.md

@@ -19,7 +19,7 @@ Rules to enforce:
 4. If no packages changed, changesets are optional; if present, they still must be consistent with the diff.
 5. Each changeset summary must be 1-2 non-empty lines.
 6. If the PR body contains GitHub issue references like #123 and a changeset exists, the changeset summary should include those references.
-7. Default bump is patch. Minor is allowed only when changes include breaking changes, dropped support, or a major feature addition. Major is allowed only after the first major release and only for changes that warrant a major release (breaking changes, dropped support, or significant behavior shifts). Before the first major release, do not use major bumps for feature-level changes. Exception: if the new feature is explicitly labeled experimental/preview in the diff (e.g., module name, docs, comments, or exports) and does not change existing behavior, a patch bump is acceptable.
+7. Default bump is patch. Require minor only when there is a breaking change, dropped support, or a behaviorally significant feature that changes existing workflows or expectations (not simply additive APIs or types). Do not require minor solely because new APIs, options, or types were added; additive features can stay patch when they do not change existing behavior. If you are unsure between patch and minor, prefer patch. Major is allowed only after the first major release and only for changes that warrant a major release (breaking changes, dropped support, or significant behavior shifts). Before the first major release, do not use major bumps for feature-level changes. Exception: if the new feature is explicitly labeled experimental/preview in the diff (e.g., module name, docs, comments, or exports) and does not change existing behavior, a patch bump is acceptable.
 8. required_bump must be "none" when there are no package changes.
 9. If unknown package directories are changed, treat it as an error.