chore: remove legacy inline action references

[wilhel1812]

Summary

• Remove the last runtime inline-action class hook from the collaborator candidate Add affordance.
• Delete the stale UI pattern glossary; README and the ActionButton audit now point to the UI Gallery as the UI source of truth.
• Add a regression assertion that the collaborator candidate Add affordance does not use inline-action.

Follow-up for #773.

Drift check

• git cherry -v origin/staging origin/main showed only the known 0.18.0 squash-policy drift tracked by Adjust staging drift workflow for squash-only PR policy #780.

Static check

• No static runtime inline-action, inline-action-icon, or action-button className usage found.
• No remaining docs/ui-pattern-glossary.md references found.

Verification

• npm run test -- --run src/components/AccessSettingsEditor.test.tsx
• npm test
• npm run build