ci: skip changeset check on the version packages PR

[nicosampler]

Summary

No related issue. The bot's "Version Packages" PR (#14) fails the changeset required check by design.

The "Version Packages" PR created by changesets/action consumes the pending changesets, so it never carries one — yet changeset-check.yml demands one on every PR against main, making the release PR permanently red. This skips the check for that PR only.

Changes

• Add if: github.head_ref != 'changeset-release/main' to the changeset job so the check skips the bot's release branch
• Add an empty changeset for this PR (CI-only change)

Acceptance criteria

• The "Version Packages" PR no longer fails the changeset check (shows as skipped)
• Regular PRs against main still require a changeset

Test plan

Automated tests

No automated tests added.

Manual verification

• On this PR, the changeset check runs and passes (head branch is not changeset-release/main)
• After merging, the next "Version Packages" PR update should show the check as skipped instead of failed

Breaking changes

None.

Checklist

• Self-reviewed my own diff
• Tests added or updated
• Docs updated (if applicable)
• No unrelated changes bundled in

Screenshots

None.

[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.