feat: add playable card system and Coatcheck suite

[superposition]

Summary

• add companion, resource, route, and decision card primitives with explicit informational/interactive semantics
• add purposeful hover/press/selection motion and reduced-motion behavior
• expand the no-reload Coatcheck workbench to 22 stories, state matrices, and a combined field-choice scene
• integrate released coatcheck 0.2.0, Bun, Playwright, Axe, review screenshots, and CI browser checks
• add reciprocal README navigation for every maintained folder

Validation

• ./scripts/check
• ./scripts/test-coatcheck — 49 passed across 22 stories × desktop/mobile plus custom interactions
• pointer, Enter, Space, disabled, reduced-motion, Axe serious/critical, console/page errors, frame markers, and overflow gates
• manual visual review of desktop/mobile field-choice and route frames
• bun install --frozen-lockfile
• shell, JavaScript, YAML, and Markdown link checks

Dependency

Uses published coatcheck = "0.2.0" from crates.io.