refactor(ui): tighten design system governance

[somewan820]

Summary

• Tighten the design system governance from issue chore(ui): design system refactor — close gap with Craft Agents #406 by separating primary CTA semantics from accent usage.
• Add the radius token vocabulary: control, surface, modal, and pill, with the 12px ceiling documented.
• Remove default decorative entrance animation while keeping intentional state/feedback motion tokens.
• Add design governance contract tests and Storybook token/animation catalog stories to prevent regressions.

Tests

• npm run typecheck
• npm --workspace @maka/ui test
• npm --workspace @maka/desktop run build-storybook
• npm --workspace @maka/desktop run build:main && node --test apps/desktop/dist/main/__tests__/design-system-governance-406-contract.test.js apps/desktop/dist/main/__tests__/ chat-preview-cascade-contract.test.js apps/desktop/dist/main/__tests__/chat-tool-card-cascade-contract.test.js apps/desktop/dist/main/__tests__/radius-converge-contract.test.js apps/desktop/dist/main/__tests__/motion-token-converge-contract.test.js
• npm test

[Astro-Han]

Pushed c1b80dc with the review-response changes.

Covered:

• expanded motion governance to scan packages/ui/src/**/*.{ts,tsx} plus renderer CSS, with only functional motion allowlisted;
• added the 1px ring through --shadow-maka-panel so Dialog and Select still have a visible edge;
• changed gap 5 to action / control tokens instead of flipping primary to foreground, with light/dark contrast contracts;
• replaced the touched chat.tsx arbitrary radius values with radius tokens;
• split token stories into Colors, Radius, and Primary Actions, tightened Colors, labeled Animation samples, and redesigned Radius so labels do not overlap.

Verified with npm run typecheck, npm test, the design-system/storybook contracts, and npm run -w @maka/desktop build-storybook. I also checked the Radius story in desktop and narrow iframe views.