rnd(M03): add rendered ground query facade

docs/modules/terrain-query.md

@@ -5,10 +5,10 @@
 | Field | Value |
 |---|---|
 | Status | Implemented |
-| Target/work package | M02 / M02-GMP-TERRAIN-QUERY-001 |
+| Target/work package | M02 / M02-GMP-TERRAIN-QUERY-001; M03 renderer consumer `M03-RND-FACADE-GROUND-QUERY-001` |
 | Owners | Gameplay terrain-query contract; ADT adapter owns parsed tile cache |
 | Last verified | `a45d521`, 2026-07-14 |
-| Profiles/capabilities | Current sandbox ADT ground height; renderer/physics backend planned |
+| Profiles/capabilities | Current sandbox ADT ground height; loaded-render-mesh diagnostic query; authoritative physics backend planned |
 
 ## Purpose
 
@@ -47,6 +47,8 @@ Allowed dependencies:
 - Existing native `ADTLoader` at the ADT adapter boundary.
 - Dynamic dictionaries only inside the native-format adapter.
 - Player scene composition may inject any `TerrainQuery` implementation.
+- Renderer diagnostics reuse `GodotWorldPosition` through `WorldRenderFacade`
+  but return renderer-owned `RenderedGroundSample`, preserving the render/gameplay boundary.
 
 Forbidden dependencies:
 
@@ -65,6 +67,7 @@ Forbidden dependencies:
 | `AdtTerrainQuery.new(extracted_directory, map_directory_name, loader_override)` | Adapter constructor | Configures one map and optional test/data-source loader | Query lifetime | Production validates native loader and file presence lazily |
 | `AdtTerrainQuery.sample_ground_height(position)` | Adapter method | Loads/caches tile and interpolates ADT outer heights | Main thread; cache lives with query | Returns stable failure code |
 | `ThirdPersonWowController.set_terrain_query(query)` | Composition method | Replaces terrain backend independently of movement/presentation | Call before scene ready or on main thread | Null is rejected and current query retained |
+| `WorldRenderFacade.sample_ground_height(position)` | Separate renderer diagnostic API | Samples already loaded terrain Mesh and returns `RenderedGroundSample` without exposing streamer state | Main thread; immutable sample | Stable `render_terrain_*` unavailable code; not injected into player by default |
 
 ## Inputs and outputs
 
@@ -206,6 +209,9 @@ Existing ADT/native/cache format versions remain unchanged.
 ## Extension points
 
 - Streaming renderer or physics backend may implement `TerrainQuery` without changing player/movement.
+- The current facade intentionally uses a separate renderer-owned result and is
+  not a `TerrainQuery` implementation. A future adapter must explicitly translate
+  readiness/results and define gameplay authority before composition.
 - Future result may grow separate slope, surface, liquid or collision contracts;
   incompatible additions require a versioned contract rather than Dictionary fields.
 - Test/authoring data sources may use constructor loader override.
@@ -218,7 +224,8 @@ Existing ADT/native/cache format versions remain unchanged.
 | Typed replaceable ground-height query | Implemented | Contract and injected player regression | Integrate target checklist after review |
 | Existing ADT height interpolation | Implemented | Synthetic fractional-grid fixture | Compare terrain contact with build 12340 |
 | Per-tile success/failure cache | Implemented | Loader call-count regression | Add explicit invalidation only with authoring/hot reload |
-| Renderer/streaming cache backend | Planned | Boundary permits replacement | M03 renderer facade/public terrain backend |
+| Renderer loaded-mesh diagnostic backend | Implemented | M03 facade typed sample and detached snapshot contract | Not composed into gameplay; triangle Mesh ray is diagnostic only |
+| Authoritative renderer/physics backend | Planned | Boundary permits replacement | Define holes/slopes/collision/readiness semantics before gameplay composition |
 | Holes/slopes/collision | Planned | Outside height-only contract | Later movement/physics package |
 | Liquid/swim query | Planned | Outside contract | M09/M12 world gameplay |
 
@@ -240,6 +247,7 @@ Existing ADT/native/cache format versions remain unchanged.
 | `src/gameplay/terrain/terrain_query.gd` | Replaceable typed query boundary |
 | `src/gameplay/terrain/adt_terrain_query.gd` | Native ADT adapter, cache, chunk selection and interpolation |
 | `src/scenes/player/third_person_wow_controller.gd` | Query composition and existing ground-snap consumer |
+| `src/render/world_render_facade.gd` | Read-only loaded-render-mesh diagnostic consumer of typed position/sample contracts |
 | `src/tools/verify_terrain_query.gd` | Synthetic contract/cache/failure/injection regression |
 | `src/tests/scenes/player_input_regression.tscn` | Asset-free player composition fixture |