refactor(M03): extract M2 mesh load pipeline state

Work-Package: M03-RND-M2-MESH-LOAD-PIPELINE-001
Agent: sindo-main-codex
Tests: 34 headless contract regressions pass; documentation and coordination gates pass; checkpoint dry-run 7/7
Fidelity: preserves request insertion polling order, terminal completion FIFO/statuses, metrics and clear/shutdown behavior; no visual parity claim

RENDER.md

@@ -36,6 +36,7 @@ Paired run 2026-07-11 подтвердил крупный coordinate/placement g
 - `src/render/liquid/adt_water_load_pipeline_state.gd` - ADT water pending FIFO/dedupe, active task IDs and worker-safe parsed-result mailbox without parser or Node ownership.
 - `src/render/liquid/adt_water_scene_finalizer.gd` - stateless main-thread ADT water build/attach and optional persisted Editor ownership through the existing ADTBuilder.
 - `src/render/m2/m2_runtime_mesh_rebuild_classifier.gd` - memoized billboard/UV-rotation decision for stale cached M2 runtime mesh refresh.
+- `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/scenes/streaming/eastern_kingdoms_streaming.tscn` - текущая сцена для проверки Azeroth/Eastern Kingdoms.
 - `addons/mpq_extractor/loaders/adt_builder.gd` - сборка ADT terrain, control splat материалов и MH2O liquids.
 - `addons/mpq_extractor/loaders/m2_builder.gd` - сборка статического M2 mesh/material.
@@ -1056,6 +1057,22 @@ $exe = Join-Path $env:TEMP 'godot-4.6.1-openwc\Godot_v4.6.1-stable_win64.exe'
 - No cache version, shader, material, geometry or visible rule changed. Synthetic
   predicate timing is not asset-backed descriptor-pressure/p95/p99 evidence.
 
+## 2026-07-17 M2 Mesh Load Pipeline State Extraction
+
+- `M2MeshLoadPipelineState` now owns static M2 successful threaded-load request
+  records and the FIFO populated when ResourceLoader polling reaches loaded or
+  failed terminal status.
+- Pending polling snapshots preserve Dictionary insertion order; terminal FIFO
+  order follows completion transition order. Existing `m2_mesh` metrics still
+  count pending plus finalize records at all three sites.
+- Shutdown still drains every pending ResourceLoader path before state clear;
+  map reset and shutdown retain the same two clear sites.
+- `StreamingWorldLoader` still selects `.tscn`/`.glb` paths, excludes animated
+  pivot-prefix GLBs, performs all ResourceLoader calls, consumes
+  `M2_MESH_FINALIZE`, extracts/prepares Meshes and updates Mesh/missing caches.
+- Cache formats, material refresh, profiles and visible output are unchanged.
+  Synthetic state timing is not asset-backed I/O, leak or p95/p99 evidence.
+
 ## 2026-07-17 WMO Placement Resolver Extraction
 
 - `WmoPlacementResolver` now owns lowercase/slash cache-key normalization,