feat: Fortnite-style OTS camera + Alt free-look orbit in third person

- Third-person camera chain is now HeadPivot > OrbitPivot > ShoulderOffset
  (0.55m right, 0.12m up) > SpringArm(2.6m, 14 deg) — the character sits
  slightly left of screen centre over-the-shoulder instead of dead centre
  behind. Aim is unchanged (still the first-person camera).
- Hold Alt in third person to orbit the camera freely around the character
  with the mouse (yaw wraps, pitch clamped -69..+29 deg); the character
  keeps facing and aiming where it was. Release Alt and the camera springs
  back behind the shoulder.
- debug/orbit_capture.gd: screenshots the OTS framing, a driven orbit, and
  the spring-back for visual regression.

Co-Authored-By: Claude Fable 5 <[email protected]>

debug/orbit_capture.gd

@@ -0,0 +1,59 @@
+extends SceneTree
+
+## Dev tool: screenshot the third-person over-the-shoulder framing, the Alt
+## free-look orbit, and the spring-back. Run:
+##   godot --path . --windowed --resolution 1280x720 -s res://debug/orbit_capture.gd -- <out_dir>
+
+var _frames := 0
+var _out_dir := "."
+var _player: Node = null
+var _rig: Node = null
+
+
+func _initialize() -> void:
+	var args := OS.get_cmdline_user_args()
+	if args.size() > 0:
+		_out_dir = args[0]
+	change_scene_to_file("res://ui/main_menu/main_menu.tscn")
+
+
+func _process(_delta: float) -> bool:
+	_frames += 1
+	if _frames == 40:
+		var sm = root.get_node_or_null("SkinManager")
+		if sm:
+			sm.set_active_skin("taila")
+		var nm = root.get_node_or_null("NetworkManager")
+		if nm and nm.has_method("start_singleplayer_match"):
+			nm.start_singleplayer_match("Deathmatch")
+		change_scene_to_file("res://scenes/maps/test_level/test_level.tscn")
+	elif _frames == 160:
+		for p in root.find_children("*", "CharacterBody3D", true, false):
+			if p.has_method("set_third_person") and p.is_multiplayer_authority():
+				_player = p
+				break
+		if not _player:
+			printerr("orbit_capture: no player")
+			return true
+		_rig = _player.get_node_or_null("HeadPivot")
+		_player.set_third_person(true)
+	elif _frames == 220:
+		_shot("ots_default")   # over-the-shoulder framing, no orbit
+	elif _frames > 220 and _frames <= 280:
+		# Simulate holding Alt: force the orbit angles every frame (the
+		# spring-back fights us since Alt isn't really down, so keep writing).
+		_rig._orbit_yaw = 1.9
+		_rig._orbit_pitch = -0.25
+	elif _frames == 281:
+		_shot("orbit_side")    # camera swung around toward the front
+	elif _frames == 320:
+		_shot("sprung_back")   # ~0.65s after release: should be behind again
+		return true
+	return false
+
+
+func _shot(tag: String) -> void:
+	var img := root.get_viewport().get_texture().get_image()
+	var path := _out_dir + "/" + tag + ".png"
+	img.save_png(path)
+	print("orbit_capture: saved ", path)

debug/spawn_smoke_test.gd

@@ -98,7 +98,8 @@ func _test_spawn_with_skin(skin_id: String, expect_skinned: bool) -> void:
 
 	# Third-person toggle: camera swap + owner model visibility.
 	if player.has_method("set_third_person"):
-		var tp_cam = player.get_node_or_null("HeadPivot/ThirdPersonBoom/ThirdPersonCamera")
+		var tp_cam = player.get_node_or_null(
+			"HeadPivot/OrbitPivot/ShoulderOffset/ThirdPersonBoom/ThirdPersonCamera")
 		_check(tp_cam != null, "third-person camera boom created")
 		player.set_third_person(true)
 		await process_frame