[aicayzer]

Summary

Reduce the changelog filter pill text size by one point and remove the visible label, keeping the controls visually quieter.

Changes

• Remove the visible “Filter by part” label while retaining an accessible group name.
• Reduce pill text from 14px to 13px.
• Update the component test for the accessible group name and explicit all-parts default.

Testing

• pnpm exec vitest run src/components/changelog.test.tsx passed (12 tests).
• pnpm run build succeeded.
• git diff --check passed.

Notes for reviewers

• Filtering and selected-state behavior are unchanged.
• The pills remain on the page background with no enclosing panel.

Checklist

• The change is covered by tests.
• The docs site build succeeds.
• No unrelated files are changed.