Koiusa Actor Runtime

Format-neutral control contracts for loadable Unity runtime actors.

The package defines actor identity, source and provider boundaries, selected-actor sessions, change notifications, and optional playback, motion, appearance, physics, and scene-object features. It does not run animation, rendering, or physics update loops, so format-specific runtimes retain their native performance characteristics.

ActorSession owns the selected actor and performs atomic replacement through an ActorProviderRegistry. IActorSession exposes busy/progress/error state, cancellation, clearing, granular change flags, and typed operation outcomes. Actors and asynchronous features may implement IActorOperationSource; the session forwards their start, success, failure, and cancellation notifications without requiring format-specific UI.

MMD support is provided by com.koiusa.actor.mmd. VRM and glTF providers can implement the same contracts without adding format-specific members to IActor.

See the repository document Documentation~/actor-runtime-architecture.md for the full architecture, lifecycle rules, performance requirements, and extension roadmap.