feat: add npc simulation, instancing and visual scene

world/world_view_manager.gd

@@ -0,0 +1,34 @@
+extends Node
+
+@export var npc_visual_scene: PackedScene
+@export var simulation_manager: Node
+@export var active_npcs_parent: Node3D
+
+var active_npc_visuals := {} # sim_id -> NPCVisual
+
+func _ready() -> void:
+	call_deferred("spawn_initial_npcs")
+
+func spawn_initial_npcs() -> void:
+	if simulation_manager == null:
+		push_error("WorldViewManager: simulation_manager is missing")
+		return
+
+	if npc_visual_scene == null:
+		push_error("WorldViewManager: npc_visual_scene is missing")
+		return
+
+	for npc in simulation_manager.npcs:
+		spawn_npc_visual(npc)
+
+func spawn_npc_visual(npc: SimNPC) -> void:
+	if active_npc_visuals.has(npc.id):
+		return
+
+	var visual := npc_visual_scene.instantiate()
+	active_npcs_parent.add_child(visual)
+
+	visual.global_position = npc.position
+	visual.setup_from_sim(npc)
+
+	active_npc_visuals[npc.id] = visual