feat: action runner + PrismScene public embed API

[ClodoCapeo]

Summary

Closes the broadcast loop for Prism's animation redesign (P6 blocker)
and makes Solar embeddable in arbitrary web pages without Pulsar, CEF,
or Electron. Three consumers, one API : Prism preview (webview), Pulsar
broadcast (CEF), web embed (host page).

Changes

• Patch.action descriptor on the wire protocol — six built-in
  kinds (count-up, curve-path, text-reveal, stagger-group,
  reorder, mask-reveal). Patches without action flow through
  the existing transitions.ts mapper untouched — fully backward
  compatible.
• animate/action-runner.ts dispatcher + per-kind sub-runners
  in animate/runners/. Unknown kinds throw UnknownActionKindError.
  Hosts can register custom runners via registerActionRunner().
• animate/flip.ts — single source of truth for FLIP. Solar's
  reorder runner consumes it directly ; Prism's preview will
  import it via @zablab/solar/animate/flip at P5.
• animate/easing-resolver.ts — EasingRef → CSS easing +
  t → eased t for runners that compute values in JS.
• PrismScene public class — mount, unmount,
  playAnimation, stopAnimation, on/off, connectToOrion,
  disconnectFromOrion, setScene. Concurrency-safe (rejects
  double plays of the same asset with code: "ALREADY_PLAYING")
  and abortable.
• DOM binder — one-way bindings via data-anim-path /
  data-anim-attr. ${param.*} interpolation through patch
  path/value and action params.
• Packaging : ESM main + ESM alias + UMD bundle +
  animate/flip subpath + public .d.ts. npm publish --dry-run
  green. Runtime gzipped budget : UMD 18.78 KiB ; ESM ~17.8 KiB.
  Well under the 80 KB criterion.
• Docs : docs/embed-on-website.md (client deliverable),
  docs/action-descriptors.md (protocol reference).
• Examples : examples/embed-vanilla/ (<script> tag) +
  examples/embed-react/ (forwardRef wrapper).
• CHANGELOG.md narrative entry for 0.2.0.
• react, react-dom, framer-motion moved to peerDependencies ;
  hosts supply their own copies.

Acceptance criteria

#	Criterion	Status
1	npm run lint && typecheck && test && build green	✅
2	Backward-compatible Patch handling	✅ (no transitions.ts change)
3	Action runner — count-up (0 → 1891 in 800ms)	✅ tests/unit/runners-count-up.test.ts
4	Action runner — reorder FLIP	✅ tests/unit/runners-reorder-flip.test.ts
5	Action runner — text-reveal stagger	✅ tests/unit/runners-text-reveal.test.ts
6	Public API — vanilla embed	✅ examples/embed-vanilla/
7	Public API — React embed	✅ examples/embed-react/
8	Packaging — UMD + ESM + flip subpath + types, ≤ 80KB gzipped	✅ runtime 18.78 KiB
9	End-to-end visual parity with Prism	⏳ Depends on Prism P6 — visual diff to run jointly

Test plan

• npm run lint && npm run typecheck clean
• npm test — 68 vitest tests green (11 suites)
• npm run build — ESM + UMD + flip subpath + types emitted
• npm publish --dry-run — tarball valid, all required artefacts present
• Manual : open examples/embed-vanilla/index.html in a browser, click the button, verify count-up animation
• Manual : drop examples/embed-react/PrismSceneEmbed.tsx into a React app, verify play prop triggers animation
• Joint E2E with Prism P6 once that chantier lands

🤖 Generated with Claude Code