refactor(M03): extract M2 animation load pipeline state

src/render/m2/m2_animation_load_pipeline_state.gd

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+class_name M2AnimationLoadPipelineState
+extends RefCounted
+
+## Owns animated M2 threaded-load request records and the terminal finalize FIFO.
+## The caller owns ResourceLoader I/O, permits, Nodes and prototype outcomes.
+
+var _request_by_normalized_path: Dictionary = {}
+var _finalize_records: Array[Dictionary] = []
+
+
+## Records one normalized M2 path and ResourceLoader path. Empty or duplicate
+## values are rejected without mutation.
+func remember_request(normalized_relative_path: String, resource_path: String) -> bool:
+	if normalized_relative_path.is_empty() or resource_path.is_empty():
+		return false
+	if _request_by_normalized_path.has(normalized_relative_path):
+		return false
+	_request_by_normalized_path[normalized_relative_path] = {
+		"normalized": normalized_relative_path,
+		"path": resource_path,
+	}
+	return true
+
+
+## Returns whether one normalized path currently has a pending threaded request.
+func has_request(normalized_relative_path: String) -> bool:
+	return (
+		not normalized_relative_path.is_empty()
+		and _request_by_normalized_path.has(normalized_relative_path)
+	)
+
+
+## Returns detached pending records in their existing Dictionary insertion order.
+func request_records_snapshot() -> Array[Dictionary]:
+	var records: Array[Dictionary] = []
+	for request_variant in _request_by_normalized_path.values():
+		var request: Dictionary = request_variant
+		records.append(request.duplicate())
+	return records
+
+
+## Removes one pending request and appends its terminal status to the finalize
+## FIFO. Unknown paths are rejected without mutation.
+func complete_request(normalized_relative_path: String, terminal_status: int) -> bool:
+	if not _request_by_normalized_path.has(normalized_relative_path):
+		return false
+	var request: Dictionary = _request_by_normalized_path[normalized_relative_path]
+	_request_by_normalized_path.erase(normalized_relative_path)
+	var finalize_record := request.duplicate()
+	finalize_record["status"] = terminal_status
+	_finalize_records.append(finalize_record)
+	return true
+
+
+## Removes one pending request without enqueuing finalization.
+func discard_request(normalized_relative_path: String) -> bool:
+	return _request_by_normalized_path.erase(normalized_relative_path)
+
+
+## Returns whether a terminal record is waiting for budgeted finalization.
+func has_finalize_record() -> bool:
+	return not _finalize_records.is_empty()
+
+
+## Removes and returns the oldest terminal record. Empty means none is ready.
+func pop_finalize_record() -> Dictionary:
+	if _finalize_records.is_empty():
+		return {}
+	return _finalize_records.pop_front()
+
+
+## Returns pending plus terminal-finalize work for existing renderer metrics.
+func total_work_count() -> int:
+	return _request_by_normalized_path.size() + _finalize_records.size()
+
+
+## Returns the pending request count.
+func pending_request_count() -> int:
+	return _request_by_normalized_path.size()
+
+
+## Returns the terminal finalize FIFO count.
+func finalize_record_count() -> int:
+	return _finalize_records.size()
+
+
+## Clears request/finalize bookkeeping. The caller must drain ResourceLoader
+## requests before orderly shutdown clear.
+func clear() -> void:
+	_request_by_normalized_path.clear()
+	_finalize_records.clear()
+
+
+## Returns detached request and finalize records without loaded Resources/Nodes.
+func diagnostic_snapshot() -> Dictionary:
+	var finalize_records: Array[Dictionary] = []
+	for record in _finalize_records:
+		finalize_records.append(record.duplicate())
+	return {
+		"requests": request_records_snapshot(),
+		"finalize_records": finalize_records,
+	}

src/render/m2/m2_animation_load_pipeline_state.gd.uid

@@ -0,0 +1 @@
+uid://h5rk6njgaujd