feat: third-person camera toggle (V) + fix first-person showing inside the model

The first-person head-shrink (SkeletonModifier3D) left the camera looking at
the inside of the neck/torso/hair. Replaced it: the owner's model now renders
shadows-only in first person (clean FPS view, still fully animated and visible
to others and in shadows).

Added a third-person toggle (V / toggle_camera_view) so you can actually see
your own animated model — the easiest way to verify a new skin's animations:
- over-the-shoulder SpringArm3D camera (wall-collision aware) on the local
  player; press V to swap, press again to return
- firing still uses the first-person camera, so aim is unchanged
- reveals the owner's model via set_owner_visible() on both SkinnedPlayerModel
  and HumanoidModel; hides the first-person weapon viewmodel while in TP
- death forces first person so the toggle can't fight the death cam

Smoke test extended to cover the toggle (camera boom created, becomes current,
round-trips) — 28/28 checks pass for both color and GLB skins.

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

movement/player_movement_controller.gd

@@ -11,6 +11,12 @@ var camera: Camera3D = null
 var flashlight: SpotLight3D = null
 var _damage_layer: CanvasLayer = null
 
+# Third-person view toggle (local player only). The first-person camera keeps
+# handling aim/firing; the toggle only changes which camera renders and whether
+# the owner sees their own model.
+var third_person: bool = false
+var _tp_camera: Camera3D = null
+
 # Health and Shield
 var max_health: float = 100.0
 var health: float = 100.0
@@ -132,10 +138,56 @@ func _ready() -> void:
 		if skin_mgr:
 			synced_skin_id = skin_mgr.active_skin_id
 		synced_position = position
+		_setup_third_person_camera()
 	# Build the visual model for whatever skin is selected (remote peers get
 	# the id via the synchronizer and rebuild in _process when it arrives).
 	_apply_skin_model(synced_skin_id)
 
+
+## Over-the-shoulder camera for the local player, on a spring arm so it doesn't
+## clip through walls. The first-person camera still exists and handles firing;
+## this one only renders when third_person is on.
+func _setup_third_person_camera() -> void:
+	if not head_pivot or not is_instance_valid(camera):
+		return
+	var boom := SpringArm3D.new()
+	boom.name = "ThirdPersonBoom"
+	boom.spring_length = 3.2
+	boom.margin = 0.3
+	boom.collision_mask = 1  # environment only
+	boom.add_excluded_object(get_rid())
+	# Aim the arm up-and-back from the head so the camera sits behind/above.
+	boom.rotation_degrees = Vector3(20, 0, 0)
+	head_pivot.add_child(boom)
+
+	_tp_camera = Camera3D.new()
+	_tp_camera.name = "ThirdPersonCamera"
+	_tp_camera.fov = camera.fov
+	_tp_camera.current = false
+	boom.add_child(_tp_camera)
+
+
+## Toggle between first- and third-person. Firing keeps using the first-person
+## camera, so aim is unchanged; only rendering and self-visibility change.
+func set_third_person(on: bool) -> void:
+	if not is_multiplayer_authority():
+		return
+	third_person = on
+	if is_instance_valid(_tp_camera):
+		_tp_camera.current = on
+	if is_instance_valid(camera):
+		camera.current = not on
+	# Reveal / hide the owner's own model.
+	var visual = get_visual_model()
+	if visual and visual.has_method("set_owner_visible"):
+		visual.set_owner_visible(on)
+	# Hide the first-person weapon viewmodel in third person (it would float in
+	# the middle of the screen); the third-person weapon on the model shows.
+	if is_instance_valid(camera):
+		var wman = camera.get_node_or_null("WeaponManager")
+		if wman and "canvas_layer" in wman and is_instance_valid(wman.canvas_layer):
+			wman.canvas_layer.visible = not on
+
 ## Returns the node that visually represents this player (skinned GLB model
 ## if the active skin has one, otherwise the procedural HumanoidModel).
 func get_visual_model() -> Node3D:
@@ -760,6 +812,9 @@ func _physics_process(_delta: float) -> void:
 			if Input.is_action_just_pressed("toggle_flashlight") and is_instance_valid(flashlight):
 				flashlight.visible = !flashlight.visible
 
+			if Input.is_action_just_pressed("toggle_camera_view"):
+				set_third_person(not third_person)
+
 		var machine := _ensure_machine()
 		if machine:
 			machine.input_dir = raw_input
@@ -1026,7 +1081,11 @@ func _setup_hud() -> void:
 func die(impulse: Vector3 = Vector3.ZERO) -> void:
 	if is_dead: return
 	is_dead = true
-	
+
+	# Return to first person so the toggle state doesn't fight the death cam.
+	if is_multiplayer_authority() and third_person:
+		set_third_person(false)
+
 	# Disable movement state machine inputs
 	if _machine:
 		_machine.process_mode = Node.PROCESS_MODE_DISABLED