docs: mark simulation definitions phase complete

docs/RESOURCE_NODE_MIGRATION.md

@@ -218,19 +218,21 @@ signal reservation_changed(node_id: StringName, agent_id: int)
 @export var node_id: StringName
 @export var action_id: StringName = &"gather_food"
 @export var resource_id: StringName = &"food"
-@export var amount_remaining: float = 10.0
+@export var initial_amount: float = 10.0
 @export var yield_per_action: float = 2.0
-@export var enabled: bool = true
+@export var initial_enabled: bool = true
 @export var can_npcs_use: bool = true
 @export var can_player_use: bool = true
 @export var hide_visual_when_depleted: bool = false
 
 @onready var interaction_point: Marker3D = $InteractionPoint
+var state: ResourceStateRecord
 ```
 
-Use `StringName` IDs as a small migration step away from duplicated free-form
-`String` values. Later, action and resource definitions can become custom
-`Resource` assets without changing every world node's conceptual contract.
+Action IDs now use canonical `SimulationIds` values and resolve through
+validated `ActionDefinition` resources. ResourceNode's exported amount and
+enabled values are initialization defaults only; its bound
+`ResourceStateRecord` owns live mutable state.
 
 ### Avoid duplicated state
 
@@ -239,7 +241,7 @@ Derive it:
 
 ```gdscript
 func is_depleted() -> bool:
-    return amount_remaining <= 0.0
+    return state.is_depleted() if state != null else initial_amount <= 0.0
 ```
 
 If regeneration or non-depleting sources later require more states, introduce