fix(M03): make WMO build queue cold-load safe

src/render/wmo/wmo_render_build_queue.gd

@@ -35,9 +35,60 @@ func front_key() -> String:
 	return _queued_placement_keys.front()
 
 
-## Returns the current typed job for a placement key, or null for a stale key.
-func job_for(placement_key: String) -> WmoRenderBuildJob:
-	return _jobs_by_placement_key.get(placement_key, null) as WmoRenderBuildJob
+## Returns whether a FIFO placement key still has a current job record.
+func has_job(placement_key: String) -> bool:
+	return _jobs_by_placement_key.has(placement_key)
+
+
+## Returns the current job record as its engine base type, or null for a stale
+## key. Runtime consumers should prefer the typed accessors below.
+func job_for(placement_key: String) -> RefCounted:
+	return _jobs_by_placement_key.get(placement_key, null) as RefCounted
+
+
+## Returns the borrowed root for a current job, or null for a stale key.
+func root_for(placement_key: String) -> Node3D:
+	var job := job_for(placement_key)
+	if job == null:
+		return null
+	return job.call("root") as Node3D
+
+
+## Returns the borrowed render resource for a current job, or null when stale.
+func render_resource_for(placement_key: String) -> Resource:
+	var job := job_for(placement_key)
+	if job == null:
+		return null
+	return job.call("render_resource") as Resource
+
+
+## Returns the current mesh cursor, or zero for a stale key.
+func mesh_index_for(placement_key: String) -> int:
+	var job := job_for(placement_key)
+	if job == null:
+		return 0
+	return int(job.call("mesh_index"))
+
+
+## Returns the current MultiMesh cursor, or zero for a stale key.
+func multimesh_index_for(placement_key: String) -> int:
+	var job := job_for(placement_key)
+	if job == null:
+		return 0
+	return int(job.call("multimesh_index"))
+
+
+## Adopts both cursors for a current job and returns whether it existed.
+func adopt_cursors(
+		placement_key: String,
+		next_mesh_index: int,
+		next_multimesh_index: int
+) -> bool:
+	var job := job_for(placement_key)
+	if job == null:
+		return false
+	job.call("adopt_cursors", next_mesh_index, next_multimesh_index)
+	return true
 
 
 ## Pops and returns the front FIFO key, or an empty String when already empty.
@@ -79,9 +130,9 @@ func diagnostic_snapshot() -> Dictionary:
 	var jobs: Array[Dictionary] = []
 	for placement_key_variant in placement_keys:
 		var placement_key := String(placement_key_variant)
-		var job := job_for(placement_key)
+		var job: RefCounted = job_for(placement_key)
 		if job != null:
-			jobs.append(job.diagnostic_snapshot())
+			jobs.append(job.call("diagnostic_snapshot") as Dictionary)
 	return {
 		"queued_placement_keys": _queued_placement_keys.duplicate(),
 		"jobs": jobs,