fix: make frame controls keyboard-safe

[ddebowczyk]

Summary

• make tab selection work through normal keyboard button activation
• give compact controls accessible labels and expanded state
• default Layman buttons to type=button so host forms do not submit
• remove internal DOM IDs that could duplicate across views
• cover focus, compact controls, reduced motion, form safety, and multi-view IDs

Verification

• npm test
• npm run lint
• npm run build:lib
• npm run typecheck:consumer
• npm run typecheck:tauri-example
• npm run check:package
• npm pack --dry-run
• markdownlint README.md docs/**/*.md
• yq . .github/workflows/ci.yml
• ast-grep outline on changed files
• git diff --check

Follow-up to the controlled-view hardening stack; merge after PR #42.