refactor(M03): extract terrain quality mesh cache

docs/modules/world-renderer.md

@@ -5,9 +5,9 @@
 | Field | Value |
 |---|---|
 | Status | Partial |
-| Target/work package | M00 baseline; `M01-RND-STREAMING-FOCUS-001`; `M01-QAR-SERVER-SPAWN-RENDERER-001`; `M03-RND-FACADE-001`; `M03-RND-STREAMING-PLANNER-001`; `M03-RND-SCHEDULER-001`; `M03-RND-INTERNAL-ACCESS-GATE-001`; `M03-RND-FACADE-GROUND-QUERY-001`; `M03-RND-FACADE-ENVIRONMENT-001`; `M03-RND-FACADE-ENTITY-001` |
+| Target/work package | M00 baseline; `M01-RND-STREAMING-FOCUS-001`; `M01-QAR-SERVER-SPAWN-RENDERER-001`; M03 facade/planner/scheduler/internal-access/ground/environment/entity packages; `M03-RND-TERRAIN-CACHE-SERVICE-001` |
 | Owners | Renderer workstream / milestone integrator |
-| Last verified | Worktree `work/sindo-main-codex/m03-facade-entity`, 2026-07-16 |
+| Last verified | Worktree `work/sindo-main-codex/m03-terrain-quality-cache`, 2026-07-16 |
 | Profiles/capabilities | `Performance`, `Balanced`, `High`, `Custom`; Blizzlike fidelity incomplete |
 
 ## Purpose
@@ -40,6 +40,8 @@ flowchart LR
     Loader --> Budget[RenderBudgetScheduler]
     Assets[Extracted WDT/ADT/M2/WMO/BLP] --> Native[Native loaders]
     Cache[Baked terrain/M2/WMO caches] --> Loader
+    Loader --> TerrainCache[TerrainQualityMeshCache]
+    TerrainCache --> Loader
     Native --> Parsed[Parsed tile/model data]
     Parsed --> Loader
     Loader --> Scene[SceneTree nodes]
@@ -103,6 +105,7 @@ from externally reading/writing loader-private queue, task, cache and tile-state
 | `quality_preset` | Exported property | Applies renderer budgets/radii | Before/at runtime depending property | Invalid combination should be diagnosed |
 | `runtime_stats_enabled` | Exported property | Enables periodic performance snapshot | Runtime mutable | Logging overhead only |
 | `hitch_profiler_enabled` | Exported property | Enables named hitch sections | Runtime mutable | Logging overhead only |
+| `TerrainQualityMeshCache.store/restore/clear` | Internal terrain service | Owns admitted full-quality revisit Mesh references and LRU | Renderer thread/map session | Rejected/missed entry leaves loader fallback unchanged |
 
 Публичным contract не считаются `StreamingWorldLoader` methods/properties,
 внутренние dictionaries, queues, job records и generated node names. Scene-owned
@@ -124,6 +127,7 @@ loader configuration remains transitional composition data, not a caller API.
 | Test input | Server-spawn render manifest | Coordinate fixture/verifier | Checkpoint capture tool | Repository-owned diagnostic data | Test-process lifetime |
 | Output | `StreamingTargetPlan` | `StreamingTargetPlanner` | Streamer queue/state apply | Immutable ephemeral value | One refresh |
 | Internal control | Per-frame lane limits and boolean permits | Streamer configuration / `RenderBudgetScheduler` | Ordered streamer drains | Scheduler-owned counters | Main thread/frame |
+| Internal cache | Full-quality terrain Mesh/source | Loader terrain upgrade / `TerrainQualityMeshCache` | Revisited tile state | Cache-retained Mesh reference | Map session until eviction/reset |
 | Output | Desired tile/detail operations | Streamer plan application | Finalize queues | Loader-owned | Cross-frame |
 | Output | Terrain/M2/WMO/liquid instances | Loader/builders | Godot world/renderer | Loader/world owner | Main-thread attach |
 | Output | Detached renderer metrics | `WorldRenderFacade` | Capture/baseline tools | Caller-owned deep copy | On demand |
@@ -161,6 +165,8 @@ flowchart TD
     T --> Q[Tile load queue]
     Q --> Parse[Worker parse/cache load]
     Parse --> R[Result queues]
+    R --> TerrainCache[TerrainQualityMeshCache store]
+    TerrainCache --> Revisit[Revisited tile state restore]
     R --> B[RenderBudgetScheduler permits]
     B --> Terrain[Terrain attach/upgrade]
     B --> M2[M2 group/MultiMesh attach]
@@ -263,6 +269,9 @@ sequenceDiagram
   `EntityId`; it owns no authoritative entity state and excludes the local player.
 - Entity presentation snapshots remain caller-owned inputs. Detached diagnostics
   expose only identity debug keys, paths and visibility, never Node/Resource/RID.
+- `TerrainQualityMeshCache` owns only full-quality revisit Mesh references and
+  LRU keys. The loader retains terrain tasks/results, tile state, source choice,
+  cache versions and every material/Node/RID finalization side effect.
 - Rendered-ground query results and diagnostic snapshots are caller-owned values;
   the facade never returns Mesh, Node, tile-state or queue references.
 - Loaded-mesh ground sampling is renderer diagnostics, not authoritative gameplay
@@ -377,6 +386,7 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 | Stable renderer facade | Implemented boundary / Partial fidelity | Facade contracts cover focus, environment, entity visuals, metrics and loaded-mesh ground query | Production consumers and fidelity remain |
 | Environment snapshot input | Implemented boundary / Partial fidelity | Immutable time contract, facade/controller delegation and checkpoint migration | Weather/indoor state and paired zone-transition fidelity remain |
 | Entity presentation commands | Implemented boundary / Prototype visuals | Versioned typed snapshot plus present/remove lifecycle and runtime service composition | Display/equipment/animation/effects and async scale path remain |
+| Terrain quality Mesh cache service | Implemented extraction | Scene-free admission/LRU/clear contract and loader delegation | Remaining terrain build/state/finalization is monolithic |
 | Pure streaming target planner | Implemented | `M03-RND-STREAMING-PLANNER-001` asset-free contract/performance regression | Queue scheduling and loaded-tile LOD application remain in streamer |
 | Bounded render budget scheduler | Implemented | `M03-RND-SCHEDULER-001` asset-free permit/cancellation/performance regression | Queue storage, worker concurrency and operation execution remain in streamer/services |
 | Gameplay/editor/tool internal-access boundary | Implemented | Access gate scans gameplay, EditorPlugin packages and terrain probe against actual private streamer declarations | Add future renderer diagnostic tools explicitly to the protected list |
@@ -414,6 +424,7 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 | `src/render/entities/entity_presentation_snapshot.gd` | Immutable contract-v1 entity visual input and validation |
 | `src/render/entities/world_entity_presenter.gd` | Main-thread entity visual subtree ownership and lifecycle |
 | `src/render/terrain/rendered_ground_sample.gd` | Immutable renderer-owned available/unavailable ground query result |
+| `src/render/terrain/terrain_quality_mesh_cache.gd` | Full-quality terrain revisit Mesh retention and LRU ownership |
 | `src/render/streaming/streaming_target_planner.gd` | Scene-free wanted/retained ADT target calculation |
 | `src/render/streaming/streaming_target_policy.gd` | Immutable renderer radius/prefetch policy |
 | `src/render/streaming/streaming_target_plan.gd` | Immutable planner result with read-only tile-key sets |
@@ -425,6 +436,7 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 | `src/tools/verify_world_environment_snapshot.gd` | Cold-start environment value normalization and invalid-input regression |
 | `src/tools/verify_world_entity_presentation.gd` | Entity snapshot, create/update/replace/remove and ownership regression |
 | `src/tools/verify_rendered_ground_sample.gd` | Cold-start renderer ground result invariant regression |
+| `src/tools/verify_terrain_quality_mesh_cache.gd` | Terrain cache admission, LRU, ownership and loader-boundary regression |
 | `src/tools/verify_streaming_target_planner.gd` | Planner behavior, dependency and bounded timing regression |
 | `src/tools/verify_render_budget_scheduler.gd` | Scheduler bounds, shared-lane priority, cancellation and timing regression |
 | `src/tools/verify_renderer_internal_access.gd` | Gameplay/EditorPlugin/registered renderer-tool boundary gate derived from private streamer fields |