feat(client): pure MoveValidator — membership is the whole test

client/scripts/npc/move_validator.gd

@@ -0,0 +1,29 @@
+class_name MoveValidator
+extends RefCounted
+## Pure §6 validation: an emitted move is legal iff its canonical key is in the
+## turn's available_moves (which NpcContent already computed from live state).
+## No state reads here — membership is the whole test. Invalid moves are not an
+## error; they are dropped and returned separately so the caller can log them.
+
+const ID_MOVES := ["reveal", "offer_quest", "give_item", "accept_item"]
+const BARE_MOVES := ["adjust_disposition", "refuse", "end_conversation", "become_hostile"]
+
+
+static func _key(move: Dictionary) -> String:
+	var name: String = move.get("name", "")
+	var args: Array = move.get("args", [])
+	if name in ID_MOVES:
+		return "%s(%s)" % [name, str(args[0])] if not args.is_empty() else name
+	return name  # bare/value moves key on the name alone
+
+
+static func validate(moves: Array, available_moves: Array) -> Dictionary:
+	var valid: Array = []
+	var dropped: Array = []
+	for move in moves:
+		var name: String = move.get("name", "")
+		if (name in ID_MOVES or name in BARE_MOVES) and _key(move) in available_moves:
+			valid.append(move)
+		else:
+			dropped.append(move)
+	return {"valid": valid, "dropped": dropped}