feat: Implement core game mechanics including player, enemies, bullets, HUD, and level setup.

scripts/ammo_pickup.gd

@@ -0,0 +1,14 @@
+extends Area2D
+
+@export_enum("AP", "HE") var ammo_type: int = 0
+@export var amount: int = 10
+
+func _ready():
+	body_entered.connect(_on_body_entered)
+
+func _on_body_entered(body):
+	if body.is_in_group("player"):
+		var turret = body.get_node_or_null("turret")
+		if turret and turret.has_method("add_ammo"):
+			turret.add_ammo(ammo_type, amount)
+			queue_free()