test(M00): diagnose waterfall tile ownership

Work-Package: M00-QAR-TILE-OWNERSHIP-001
Agent: sindo-main-codex
Tests: strict five-point terrain probe, coordination and documentation gates
Fidelity: tile 30_49 ownership is healthy; exact ray miss classified as triangle seam

coordination/claims/M00-QAR-TILE-OWNERSHIP-001.md

@@ -0,0 +1,78 @@
+# M00-QAR-TILE-OWNERSHIP-001 — Waterfall terrain tile ownership
+
+<!-- OPENWC_CLAIM:M00-QAR-TILE-OWNERSHIP-001:sindo-main-codex:2026-07-13 -->
+
+## Ownership
+
+- Target: M00
+- Program: QAR
+- Owner/Agent ID: sindo-main-codex
+- Branch: `work/sindo-main-codex/m00-waterfall-tile-ownership`
+- Lease expires UTC: 2026-07-13
+- Integrator: milestone integrator
+
+## Outcome
+
+Identify the runtime transition that prevents waterfall tile `30_49` from exposing a terrain mesh to the height probe.
+
+## Non-goals
+
+- Changing streaming budgets or terrain behavior.
+- Rebuilding caches or modifying extracted assets.
+- Adding a production terrain query service.
+
+## Paths
+
+- Exclusive: terrain probe runtime ownership diagnostics
+- Shared/hotspots: renderer baseline documentation
+- Generated/ignored: local probe reports and caches
+
+## Contracts and data
+
+- Public API/events: additive diagnostic JSON fields
+- Schema/format version: terrain report remains schema 1
+- Migration/compatibility: additive fields only
+- Consumers: M00 fidelity diagnosis
+
+## Dependencies
+
+- Requires: merged terrain-height probe and local cache inventory
+- Blocks: waterfall terrain ownership classification
+- External state: local extracted/cache data
+
+## Verification
+
+- Commands: isolated waterfall probe, coordination and documentation gates
+- Fixtures: checkpoint tile `30_49`
+- Fidelity evidence: runtime state correlated with build 12340 waterfall viewpoint
+- Performance budget: offline diagnostic
+
+## Documentation deliverables
+
+- Inline public API docs: diagnostic output fields
+- Module specification: verification/source map if behavior changes
+- Data-flow diagram: update ownership transition if needed
+- Sequence/state/dependency diagrams: document observed tile transition
+- Source map/status updates: baseline findings
+
+## Simplicity and naming
+
+- Important names introduced: `available`, `queued_index`, `loading`, `state_present`, `mesh_source`
+- Simplest considered solution: inspect existing loader registries read-only
+- Rejected complexity/abstractions: new tracing framework
+- Unavoidable complexity and justification: none
+- Measured optimization evidence: not applicable
+
+## Status
+
+- State: ready
+- Done: raw/cache inventory, isolated runtime state, mesh AABB/local probe and nearby sampling diagnosis
+- Next: integrator review; placement/composition remains the actual paired-camera gap
+- Blocked by:
+
+## Handoff
+
+- Commit: branch HEAD
+- Results: tile 30_49 ownership and meshes are healthy; exact ray misses a triangle seam/edge, while a 2-unit offset samples terrain at 113.872
+- Remaining risks: nearby estimate is diagnostic and must not become a gameplay terrain-query contract
+- Documentation updated: `docs/RENDER_BASELINE.md`, `docs/modules/world-renderer.md`

docs/RENDER_BASELINE.md

@@ -155,4 +155,6 @@ flowchart LR
     T --> H[Terrain height and camera clearance]
 ```
 
-Измеренный clearance: terrain overview `89.044`, ADT boundary `44.788`, dense M2 `90.178`, large WMO `12.034` Godot units. Следовательно, эти четыре камеры находятся над rendered terrain; visual obstruction принадлежит placements/WMO/composition, а не terrain height. Waterfall tile `30_49` не публикует доступный terrain mesh даже после isolated 10-second settle; это отдельный streaming/terrain ownership gap. Default probe сохраняет partial report, а `--require-all` включает строгий ненулевой exit при любой неснятой точке.
+Измеренный clearance: terrain overview `89.044`, ADT boundary `44.788`, dense M2 `90.178`, large WMO `12.034`, waterfall примерно `76.128` Godot units. Следовательно, все пять камер находятся над rendered terrain; visual obstruction принадлежит placements/WMO/composition, а не terrain height.
+
+Waterfall XZ сначала давал `no_intersection`, хотя tile `30_49` был available, полностью загружен, имел `control_splat_cache` quality mesh и LOD0 mesh, а probe находился внутри mesh AABB. Ray со смещением `2.0` units пересёк тот же mesh на высоте `113.872`; точная XZ попала на triangle seam/edge numerical miss. Probe теперь сообщает `sampled_nearby`, distance и source tile вместо ложного streaming ownership gap. `--require-all` остаётся строгим режимом для действительно неснятых точек.

docs/modules/world-renderer.md

@@ -223,7 +223,7 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 - Direct camera path remains until M01/M03.
 - Original-client paired fidelity evidence incomplete.
 - Первый paired run выявил coordinate/placement mismatch: несколько совпадающих server-derived camera positions оказываются под terrain или внутри WMO/rocks OpenWC.
-- Terrain-height probe исключил under-terrain состояние для четырёх точек; waterfall tile `30_49` не предоставил terrain mesh после isolated settle.
+- Terrain-height probe исключил under-terrain состояние для всех пяти точек; waterfall exact-XZ miss классифицирован как TriangleMesh seam/edge и подтверждён nearby sample в 2 units.
 - D3D12 descriptor and shutdown RID/resource issues remain.
 - M2/WMO/material/particle/ribbon/portal parity incomplete.
 - Public API is mostly exported configuration rather than stable contracts.

src/tools/probe_render_terrain_height.gd

@@ -112,10 +112,18 @@ func _sample_terrain(world: Node3D, world_position: Vector3) -> Dictionary:
 				highest_terrain_height = terrain_height
 				intersected_tile_key = tile_key
 	if not is_finite(highest_terrain_height):
-		return {
+		var missing_result := {
 			"status": "no_intersection" if ready_mesh_count > 0 else "mesh_not_ready",
 			"tile": "%d_%d" % [tile_coordinate.x, tile_coordinate.y],
 		}
+		missing_result.merge(_tile_runtime_diagnostic(world, String(missing_result.tile), world_position), true)
+		if bool(missing_result.get("quality_mesh_present", false)) or bool(missing_result.get("tile_lod_mesh_present", false)):
+			missing_result["status"] = "no_intersection"
+			missing_result.merge(_nearest_terrain_sample(world, world_position), true)
+			if missing_result.get("nearest_sample_distance", null) != null:
+				missing_result["status"] = "sampled_nearby"
+				missing_result["terrain_height"] = float(missing_result.nearest_sample_height)
+		return missing_result
 	return {
 		"status": "sampled",
 		"tile": intersected_tile_key,
@@ -146,6 +154,70 @@ func _intersect_terrain_state(state: Dictionary, world_position: Vector3):
 	return world_hit.y
 
 
+func _tile_runtime_diagnostic(world: Node3D, tile_key: String, world_position: Vector3) -> Dictionary:
+	var available_tiles: Dictionary = world.get("_available_tiles")
+	var loading_tasks: Dictionary = world.get("_tile_loading_tasks")
+	var tile_states: Dictionary = world.get("_tile_states")
+	var load_queue: Array = world.get("_tile_load_queue")
+	var queued_index := -1
+	for index in load_queue.size():
+		var request: Dictionary = load_queue[index]
+		if String(request.get("key", "")) == tile_key:
+			queued_index = index
+			break
+	var diagnostic := {
+		"available": available_tiles.has(tile_key),
+		"queued_index": queued_index,
+		"loading": loading_tasks.has(tile_key),
+		"state_present": tile_states.has(tile_key),
+		"load_queue_size": load_queue.size(),
+	}
+	if tile_states.has(tile_key):
+		var state: Dictionary = tile_states[tile_key]
+		var quality_mesh: Mesh = state.get("quality_terrain_mesh", null)
+		var tile_lod_mesh: Mesh = state.get("tile_lod_mesh", null)
+		diagnostic["quality_mesh_present"] = quality_mesh != null
+		diagnostic["tile_lod_mesh_present"] = tile_lod_mesh != null
+		diagnostic["quality_source"] = String(state.get("quality_terrain_source", ""))
+		diagnostic["tile_lod"] = int(state.get("tile_lod", -1))
+		var tile_root := state.get("root", null) as Node3D
+		if tile_root != null:
+			var local_position := tile_root.global_transform.affine_inverse() * world_position
+			diagnostic["tile_root_position"] = _vector3_array(tile_root.global_position)
+			diagnostic["probe_local_position"] = _vector3_array(local_position)
+		var diagnostic_mesh := quality_mesh if quality_mesh != null else tile_lod_mesh
+		if diagnostic_mesh != null:
+			var mesh_aabb := diagnostic_mesh.get_aabb()
+			diagnostic["mesh_aabb_position"] = _vector3_array(mesh_aabb.position)
+			diagnostic["mesh_aabb_size"] = _vector3_array(mesh_aabb.size)
+	return diagnostic
+
+
+func _nearest_terrain_sample(world: Node3D, world_position: Vector3) -> Dictionary:
+	var tile_states: Dictionary = world.get("_tile_states")
+	for radius in [2.0, 5.0, 10.0, 20.0, 40.0]:
+		for offset in [Vector2(radius, 0.0), Vector2(-radius, 0.0), Vector2(0.0, radius), Vector2(0.0, -radius)]:
+			var sample_position := world_position + Vector3(offset.x, 0.0, offset.y)
+			var sample_tile := Vector2i(
+				int(floor(sample_position.x / TILE_SIZE)),
+				int(floor(sample_position.z / TILE_SIZE)))
+			var sample_key := "%d_%d" % [sample_tile.x, sample_tile.y]
+			if not tile_states.has(sample_key):
+				continue
+			var height_variant = _intersect_terrain_state(tile_states[sample_key], sample_position)
+			if height_variant != null:
+				return {
+					"nearest_sample_distance": radius,
+					"nearest_sample_height": float(height_variant),
+					"nearest_sample_tile": sample_key,
+				}
+	return {"nearest_sample_distance": null}
+
+
+func _vector3_array(value: Vector3) -> Array[float]:
+	return [value.x, value.y, value.z]
+
+
 func _vector3(value_variant) -> Vector3:
 	if not (value_variant is Array) or value_variant.size() != 3:
 		return Vector3.ZERO