[codex] Harden dynamic clip parameter updates

[meekmachine]

Summary

Fixes #116.

This hardens updateClipParams() for scheduler-driven dynamic clips so active snippet/clip actions can be adjusted without rebuilding their underlying clips.

What changed

• Treat actionId as an exact selector instead of also updating broad name matches.
• Dedupe the same mixer action when it appears in both internal action maps.
• Preserve the current loop mode when only repeatCount changes.
• Support reverse updates without requiring a simultaneous rate update.
• Keep dynamic clip weight updates on the active mixer action through setEffectiveWeight().
• Return false only when no active clip/action target can be found.
• Add regression coverage for actionId targeting, no-rebuild weight updates, repeat/reverse updates, and missing action IDs.

Validation

• npx vitest run src/engines/three/AnimationThree.playbackState.test.ts
• npm run typecheck
• npm test
• npm run build
• git diff --check

[meekmachine]

PR backlog triage — CLOSE (abandoned)

Abandoned draft with no active Embody/Polymer consumer. RuntimeCore/bindings work continues elsewhere; lip-sync planners belong in Polymer.

Plan: meekmachine/Polymer#59