render: extract M2 Mesh resource finalizer

RENDER.md

@@ -47,6 +47,7 @@ Paired run 2026-07-11 подтвердил крупный coordinate/placement g
 - `src/render/m2/m2_cached_animation_resource_observer.gd` - cached animated GLB eligibility, threaded request admission and snapshot production.
 - `src/render/m2/m2_animation_load_pipeline_state.gd` - animated M2 threaded-load request records and completion-order finalize FIFO without I/O or Node ownership.
 - `src/render/m2/m2_animation_resource_finalizer.gd` - cached animated M2 terminal status polling, Resource load, scene finalization and prototype/static-only outcome.
+- `src/render/m2/m2_mesh_resource_finalizer.gd` - static M2 terminal status polling, Mesh extraction/preparation and cache/missing outcome.
 - `src/render/m2/m2_mesh_load_pipeline_state.gd` - static M2 threaded-load request records, terminal statuses and completion-order finalize FIFO without I/O or Mesh ownership.
 - `src/render/m2/m2_mesh_resource_cache_state.gd` - normalized-path prepared static M2 Mesh references with final-shutdown lifetime.
 - `src/render/m2/m2_mesh_resource_extractor.gd` - first-Mesh selection from direct/PackedScene/Node inputs with temporary instance cleanup.
@@ -1169,6 +1170,22 @@ $exe = Join-Path $env:TEMP 'godot-4.6.1-openwc\Godot_v4.6.1-stable_win64.exe'
 - No request order, status rule, cache format, profile or visible behavior changed.
   Synthetic fixtures are not asset-backed animation/leak/p95/p99 evidence.
 
+## 2026-07-18 M2 Mesh Resource Finalizer Extraction
+
+- `M2MeshResourceFinalizer` now owns static M2 terminal status polling,
+  completion-FIFO pops, terminal Resource retrieval, first-Mesh extraction,
+  stale/current runtime preparation and Mesh/missing cache adoption.
+- Pending paths are still polled in insertion order. One
+  `M2_MESH_FINALIZE` permit still pops at most one terminal record; cached Mesh
+  outcomes skip terminal retrieval exactly as before.
+- Current Meshes retain exact identity and skip raw reads. Stale Meshes still
+  request raw data only when `M2RuntimeMeshFinalizer` requires it, preserving
+  refresh-version, rebuild and original-Mesh fallback rules.
+- `StreamingWorldLoader` retains request admission, scheduler permits,
+  composition, static materialization and shutdown drain ordering. Cache paths,
+  profiles and visible behavior are unchanged; synthetic fixtures are not
+  asset-backed visual/leak/p95/p99 evidence.
+
 ## 2026-07-18 M2 Native Animation Resource Observer Extraction
 
 - `M2NativeAnimationResourceObserver` now owns the exact case-insensitive
@@ -1244,12 +1261,14 @@ $exe = Join-Path $env:TEMP 'godot-4.6.1-openwc\Godot_v4.6.1-stable_win64.exe'
 
 - `M2RuntimeMeshFinalizer` now owns material refresh version `2`, stale-Mesh
   rebuild classification, M2Builder rebuild and original-Mesh fallback.
-- Current Meshes still skip raw `.m2` loading. `M2RawModelRepository` now owns
-  FileAccess/ClassDB M2Loader I/O and supplies raw data through the loader only
-  when the finalizer reports a stale Mesh; both historical clear sites persist.
+- Current Meshes still skip raw `.m2` loading. `M2RawModelRepository` owns
+  FileAccess/ClassDB M2Loader I/O and supplies raw data through
+  `M2MeshResourceFinalizer` only when the runtime finalizer reports a stale Mesh;
+  both historical clear sites persist.
 - Billboard/UV-rotation predicates, rebuild extraction, metadata key and failure
-  fallback are unchanged. Cache adoption decisions, permits and MultiMesh
-  materialization remain loader-owned; negative outcomes belong to prototype state.
+  fallback are unchanged. Mesh resource finalization owns cache adoption;
+  permits and MultiMesh materialization remain loader-owned, while negative
+  outcomes belong to prototype state.
 - Synthetic triangle rebuild/fallback timing is not asset-backed material,
   descriptor-pressure/leak or p95/p99 evidence.