[codex] Add base pose runtime API

[meekmachine]

Summary

• Add versioned pose snapshot types that capture skeleton transforms, FACS AU values, and mesh-scoped morph influences.
• Add Loom3 runtime APIs for capturePose, applyPose, setBasePose, resetToBasePose, resetToImportedRestPose, and setBaseExpression.
• Capture the imported GLB/rest pose on onReady(...), carry profile-backed characterPoses / basePoseId / basePose through preset/profile extension, and add coverage for base pose resets.

Why

LoomLarge can now save/edit poses, but it needs Loom3 to own the actual reset/apply behavior. Base expressions are represented as FACS AU values and captured with their resolved constituent parts, so the base pose can restore both the semantic AU state and the concrete morph/bone state.

Validation

• npm run typecheck
• npm test -- --run src/engines/three/Loom3.basePose.test.ts src/characters/extendCharacterConfigWithPreset.test.ts src/mappings/extendPresetWithProfile.test.ts
• npm run build

Paired LoomLarge PR: meekmachine/LoomLarge#555
Related: meekmachine/LoomLarge#552

[meekmachine]

PR backlog triage — REBASE_KEEP

Still wanted on the Polymer / agencySociety / host plan.

Next step: rebase onto current main, resolve conflicts, ensure CI green, then undraft (if draft) for merge.

Base pose Embody API — rebase conflicts.

Plan: https://github.com/meekmachine/Polymer/discussions/59