feat(ui): make suggest panel collapsible

[JArmandoAnaya]

Summary

• add an open-by-default reduced control to the editor Suggest notice
• retain proposal guidance, Accept, and Discard while a suggestion is reduced
• preserve canvas keyboard focus after pointer activation and use state-accurate control labels
• cover expanded, reduced, minimal, narrow-viewport, and reduced-action states with browser tests

Validation

• pnpm --filter @visionset/ui-core test -- src/annotator/suggestPanel.test.tsx — 75 passed
• Docker-backed Playwright layout scenarios — 4 passed

The local Docker demo remains available for visual review.