Add profile-defined viseme mapping system

[meekmachine]

Summary

• Adds profile-owned viseme system fields: visemeSystemId, visemeSlots, visemeBindings, visemeMeshCategory, and mappingSections.
• Moves CC4 viseme slots and mapping section ordering into the CC4 preset instead of consumers hardcoding those semantics.
• Adds shared helpers for mapping-editor models, regex candidate classification, provider viseme adaptation, and live/baked viseme mesh routing.
• Adds runtime setVisemeById / transitionVisemeById APIs while keeping index APIs for compatibility.

Verification

• npm run typecheck
• npm test
• npm run build

Closes #126
Closes #127
Closes #128
Closes #129
Closes #130