refactor(M03): extract M2 animated scene finalizer

docs/modules/m2-animation-load-pipeline-state.md

@@ -14,8 +14,9 @@
 
 Own cross-frame bookkeeping between a successful animated M2 ResourceLoader
 request, terminal polling and budgeted main-thread scene finalization. This is
-an exact state extraction; animation eligibility, loading and Node lifecycle
-remain in `StreamingWorldLoader` and `M2PrototypeCacheState`.
+an exact state extraction; animation eligibility and loading remain in
+`StreamingWorldLoader`, while scene finalization and retained Node lifecycle
+belong to `M2AnimatedSceneFinalizer` and `M2PrototypeCacheState`.
 
 ## Non-goals
 
@@ -178,8 +179,9 @@ no rebake or migration is required.
 
 ## Extension points
 
-ResourceLoader polling or animated-scene finalization may later move behind
-separate adapters without changing this value-only state contract.
+ResourceLoader polling may later move behind a separate adapter without
+changing this value-only state contract. Animated-scene finalization is now a
+sibling service.
 
 ## Capability status
 
@@ -200,12 +202,14 @@ separate adapters without changing this value-only state contract.
 | Path | Responsibility |
 |---|---|
 | `src/render/m2/m2_animation_load_pipeline_state.gd` | Pending records, completion FIFO and metrics |
+| `src/render/m2/m2_animated_scene_finalizer.gd` | Candidate instantiation, material repair and player validation |
 | `src/render/m2/m2_prototype_cache_state.gd` | Animated prototype/static-only outcomes |
 | `src/scenes/streaming/streaming_world_loader.gd` | Eligibility, I/O, permits, instantiation and adoption |
 | `src/tools/verify_m2_animation_load_pipeline_state.gd` | Lifecycle/boundary/timing regression |
 
 ## Related decisions and references
 
+- [`m2-animated-scene-finalizer.md`](m2-animated-scene-finalizer.md)
 - [`m2-prototype-cache-state.md`](m2-prototype-cache-state.md)
 - [`m2-mesh-load-pipeline-state.md`](m2-mesh-load-pipeline-state.md)
 - [`world-renderer.md`](world-renderer.md)