fix(hud): have game mode hand HUD its target ship instead of group lookup

HUDController found its ship via get_first_node_in_group("ship"), a group
that has 2+ members once a match has an AI opponent — it only worked
because the player ship happened to spawn first. spawn_camera_rig now
wires the HUD's ship the same way it already wires the camera rig's
target.

Game/scripts/HUDController.gd

@@ -1,7 +1,9 @@
-# HUD Controller - discovers the ship/camera/game mode via groups and routes
-# their signals to the display widgets. All flight data is rendered by
-# aircraft-style instruments (attitude indicator, heading tape, bar gauges) —
-# this node is only the wiring hub; the instruments are dumb displays.
+# HUD Controller - receives its target ship from the game mode (see
+# GameMode.spawn_camera_rig), discovers the camera rig/game mode via groups,
+# and routes their signals to the display widgets. All flight data is
+# rendered by aircraft-style instruments (attitude indicator, heading tape,
+# bar gauges) — this node is only the wiring hub; the instruments are dumb
+# displays.
 extends CanvasLayer
 class_name HUDController
 
@@ -33,10 +35,11 @@ func _ready():
 	_initialize_hud()
 
 func _initialize_hud():
-	# Find the ship
-	ship = get_tree().get_first_node_in_group("ship")
+	# `ship` is assigned by the game mode (GameMode.spawn_camera_rig) before
+	# this runs — not discovered via group, since the "ship" group can have
+	# 2+ members and there's no reliable way to tell which one is "ours".
 	if not ship:
-		push_error("HUDController: No ship found in 'ship' group")
+		push_error("HUDController: No ship assigned")
 		return
 
 	print("HUDController: Found ship: ", ship.name)

Game/scripts/game_mode.gd

@@ -13,6 +13,7 @@ extends Node3D
 const CAMERA_RIG_SCENE = preload("res://scenes/ship_camera_rig.tscn")
 
 var arena: Arena
+var hud: HUDController
 var ball: RigidBody3D
 var ships: Array[Ship] = []
 var _ship_spawn_transforms := {}
@@ -30,7 +31,8 @@ func _ready():
 	for child in get_children():
 		if child is Arena:
 			arena = child
-			break
+		elif child is HUDController:
+			hud = child
 	if not arena:
 		var path := _get_arena_scene_path()
 		if not path.is_empty():
@@ -99,6 +101,10 @@ func spawn_camera_rig(target: Ship) -> ShipCameraRig:
 	var rig: ShipCameraRig = CAMERA_RIG_SCENE.instantiate()
 	add_child(rig)
 	rig.target = target
+	# Also wires the scene's static HUD (if any) to the same ship, rather
+	# than letting it guess via the "ship" group.
+	if hud:
+		hud.ship = target
 	return rig