feat(*): Add self-play RL training pipeline with PPO trainer, in-game GDScript policy inference, and bot opponent support in Match mode

Game/scripts/rl_ship_controller.gd

@@ -0,0 +1,14 @@
+class_name RLShipController
+extends ShipController
+
+# Controller for externally-driven ships (RL training and trained-policy
+# inference). Something else — a ShipAIController during training, an
+# AIShipController at play time — writes into `action`; the ship pulls it
+# each physics tick like any other controller. The ship never knows it is
+# being trained.
+
+var action: ShipAction = ShipAction.new()
+
+
+func get_action() -> ShipAction:
+	return action