refactor(M03): extract ADT water scene finalizer

docs/modules/adt-water-load-pipeline-state.md

@@ -38,8 +38,9 @@ flowchart LR
     State --> Result[Parsed ADT result]
     Result --> Loader
     Loader --> Budget[WATER_FINALIZE permit]
-    Loader --> Builder[ADTBuilder water scene]
-    Builder --> Scene[Main-thread tile Node attach]
+    Loader --> Finalizer[AdtWaterSceneFinalizer]
+    Finalizer --> Builder[ADTBuilder water scene]
+    Finalizer --> Scene[Main-thread tile Node attach]
 ```
 
 Allowed dependencies are RefCounted, Dictionary/Array/String and one Godot
@@ -127,7 +128,7 @@ sequenceDiagram
     participant State as AdtWaterLoadPipelineState
     participant Worker as WorkerThreadPool task
     participant Budget as RenderBudgetScheduler
-    participant Builder as ADTBuilder
+    participant Finalizer as AdtWaterSceneFinalizer
     Loader->>State: enqueue_request(tile key, ADT path)
     Loader->>State: take_next_request()
     Loader->>Worker: add_task(parse binding)
@@ -140,8 +141,8 @@ sequenceDiagram
     Loader->>Worker: wait_for_task_completion(task ID)
     Loader->>State: complete_active_task(key)
     Loader->>Loader: reject stale tile/path/root
-    Loader->>Builder: build_tile_water_scene(data, origin)
-    Loader->>Loader: attach Node and mark water_loaded
+    Loader->>Finalizer: attach_water_scene(data, origin, tile root, editor owner)
+    Loader->>Loader: mark water_loaded
 ```
 
 ## Dependency diagram
@@ -151,10 +152,11 @@ flowchart TB
     Loader[StreamingWorldLoader] --> State[AdtWaterLoadPipelineState]
     Loader --> Scheduler[RenderBudgetScheduler]
     Loader --> Worker[WorkerThreadPool / ADTLoader]
-    Loader --> Builder[ADTBuilder / SceneTree]
+    Loader --> Finalizer[AdtWaterSceneFinalizer]
+    Finalizer --> Builder[ADTBuilder / SceneTree]
     Worker -->|publish only| State
     State -. no dependency .-> Scheduler
-    State -. no dependency .-> Builder
+    State -. no dependency .-> Finalizer
 ```
 
 ## Ownership, threading and resources
@@ -163,7 +165,8 @@ flowchart TB
 - Worker threads may call only `publish_result`; result observe/pop/clear also lock.
 - Parsed water Dictionary identity is retained until main-thread pop.
 - Loader owns WorkerThreadPool task lifetime and must wait before orderly shutdown clear.
-- Loader owns tile states, ADTBuilder, water Nodes and every render resource.
+- Loader owns tile states and the tile subtree; `AdtWaterSceneFinalizer` performs
+  the main-thread ADTBuilder call and attachment without retaining Nodes.
 - `clear` cannot cancel a worker; post-reset publication becomes a stale result
   and is discarded because no active task/tile ownership remains.
 
@@ -211,8 +214,8 @@ versions are unchanged; no migration or rebuild is required.
 ## Extension points
 
 - ADT parse execution can later move behind a parser/job adapter without changing state.
-- Water scene materialization can be extracted separately because it owns Nodes
-  and main-thread effects rather than async bookkeeping.
+- Water scene materialization is now delegated to `AdtWaterSceneFinalizer`,
+  independently of this async bookkeeping service.
 
 ## Capability status
 
@@ -220,7 +223,7 @@ versions are unchanged; no migration or rebuild is required.
 |---|---|---|---|
 | ADT water load pipeline state | Implemented extraction | FIFO/task/thread/source/timing verifier | Asset-backed traversal/leak evidence pending |
 | ADT liquid parsing | Existing/loader-owned adapter | Native ADTLoader and dry-run paths | MH2O/MCLQ fidelity fixtures pending |
-| Water scene finalization | Existing/loader-owned | Scheduler/material/shutdown regressions | Separate materialization extraction possible |
+| Water scene finalization | Implemented extraction | Dedicated synthetic scene/ownership verifier | Asset-backed traversal/hitch evidence pending |
 
 ## Known gaps and risks
 
@@ -235,13 +238,15 @@ versions are unchanged; no migration or rebuild is required.
 | Path | Responsibility |
 |---|---|
 | `src/render/liquid/adt_water_load_pipeline_state.gd` | Request/task/result bookkeeping and result mutex |
-| `src/scenes/streaming/streaming_world_loader.gd` | Parse task execution, permits, stale checks and Node finalization |
+| `src/render/liquid/adt_water_scene_finalizer.gd` | Main-thread ADTBuilder call, attach and optional editor ownership |
+| `src/scenes/streaming/streaming_world_loader.gd` | Parse task execution, permits, stale checks and tile loaded timing |
 | `addons/mpq_extractor/loaders/adt_builder.gd` | ADT liquid geometry/material construction |
 | `src/tools/verify_adt_water_load_pipeline_state.gd` | Lifecycle/thread/boundary/timing regression |
 
 ## Related decisions and references
 
 - [`world-renderer.md`](world-renderer.md)
+- [`adt-water-scene-finalizer.md`](adt-water-scene-finalizer.md)
 - [`render-budget-scheduler.md`](render-budget-scheduler.md)
 - [`../../RENDER.md`](../../RENDER.md)
 - [`../../targets/roadmap/02-rendering-and-graphics.md`](../../targets/roadmap/02-rendering-and-graphics.md)