rnd(M03): add rendered ground query facade

src/render/terrain/rendered_ground_sample.gd

@@ -0,0 +1,50 @@
+class_name RenderedGroundSample
+extends RefCounted
+
+## Immutable result of sampling currently loaded render terrain in Godot world units.
+## This diagnostic value is renderer-owned and is not authoritative gameplay collision.
+
+var is_available: bool:
+	get:
+		return _is_available
+
+var height_units: float:
+	get:
+		return _height_units
+
+var failure_code: StringName:
+	get:
+		return _failure_code
+
+var _is_available: bool
+var _height_units: float
+var _failure_code: StringName
+
+
+## Creates an available finite rendered-ground sample in Godot world units.
+static func available(height_units_value: float) -> RenderedGroundSample:
+	return RenderedGroundSample.new(true, height_units_value, &"")
+
+
+## Creates an unavailable rendered-ground sample with a stable failure code.
+static func unavailable(failure_code_value: StringName) -> RenderedGroundSample:
+	return RenderedGroundSample.new(false, 0.0, failure_code_value)
+
+
+func _init(
+		is_available_value: bool,
+		height_units_value: float,
+		failure_code_value: StringName
+) -> void:
+	_is_available = is_available_value and is_finite(height_units_value)
+	_height_units = height_units_value if _is_available else 0.0
+	if _is_available:
+		_failure_code = &""
+	elif not is_finite(height_units_value):
+		_failure_code = &"render_terrain_height_not_finite"
+	else:
+		_failure_code = (
+			failure_code_value
+			if not failure_code_value.is_empty()
+			else &"render_terrain_unavailable"
+		)

src/render/terrain/rendered_ground_sample.gd.uid

@@ -0,0 +1 @@
+uid://c744ldnnn87a8

src/render/world_render_facade.gd

@@ -7,6 +7,7 @@ extends Node
 
 const GODOT_WORLD_POSITION_SCRIPT := preload("res://src/domain/coordinates/godot_world_position.gd")
 const STREAMING_FOCUS_SCRIPT := preload("res://src/domain/streaming/streaming_focus.gd")
+const RENDERED_GROUND_SAMPLE_SCRIPT := preload("res://src/render/terrain/rendered_ground_sample.gd")
 
 ## Internal renderer implementation resolved relative to this node.
 ## The referenced node remains owned by its scene parent.
@@ -66,6 +67,33 @@ func renderer_metrics_snapshot() -> Dictionary:
 	return (metrics_variant as Dictionary).duplicate(true)
 
 
+## Samples the currently loaded render terrain at a typed Godot world position.
+## This read-only renderer view is diagnostic and does not replace authoritative
+## gameplay collision or the independently composed [TerrainQuery].
+func sample_ground_height(godot_world_position: GodotWorldPosition) -> RefCounted:
+	var loader := _resolve_streaming_world_loader()
+	if loader == null:
+		return RENDERED_GROUND_SAMPLE_SCRIPT.unavailable(&"render_facade_unavailable")
+	var sample_variant = loader.call("sample_rendered_ground_height", godot_world_position)
+	if sample_variant is RefCounted and sample_variant.get_script() == RENDERED_GROUND_SAMPLE_SCRIPT:
+		return sample_variant
+	push_error("WorldRenderFacade received an invalid rendered ground sample.")
+	return RENDERED_GROUND_SAMPLE_SCRIPT.unavailable(&"render_ground_sample_invalid")
+
+
+## Returns a detached diagnostic snapshot for one rendered-ground query.
+## Mutating the result cannot mutate streamer queues, tile state or resources.
+func renderer_ground_query_snapshot(godot_world_position: GodotWorldPosition) -> Dictionary:
+	var loader := _resolve_streaming_world_loader()
+	if loader == null:
+		return {}
+	var snapshot_variant = loader.call("render_ground_query_snapshot", godot_world_position)
+	if not (snapshot_variant is Dictionary):
+		push_error("WorldRenderFacade received a non-Dictionary ground query snapshot.")
+		return {}
+	return (snapshot_variant as Dictionary).duplicate(true)
+
+
 func _capture_streaming_focus_from_source() -> void:
 	if streaming_focus_source_path == NodePath():
 		return
@@ -99,6 +127,8 @@ func _resolve_streaming_world_loader() -> Node:
 		&"set_streaming_focus",
 		&"refresh_streaming_focus",
 		&"render_baseline_snapshot",
+		&"sample_rendered_ground_height",
+		&"render_ground_query_snapshot",
 	]:
 		if not candidate.has_method(required_method):
 			if not _missing_loader_reported: