feat(cockpit): replace procedural cockpit with twelve scripted models

Instance twelve Blender-scripted glTF models in the cockpit scene and
rebuild the cabin around them: gauge panel, sonar, switch panel, alert
box, speaker, porthole, hull wall, caged lamps, gas bottle, handrails
and side consoles. Presentation only; no domain, application or world
rule changes beyond enabling glow in the test environment.

- Needles, alert lamps and sonar screen are driven by the existing
  snapshots; the alert box now carries SYS/ATTN/ALRM.
- Depth dial reads percent of certified depth.
- Sonar display restyled as a turquoise holographic relief with a
  shader grid and height scale; SubViewport matches the glass (960x604).
- Cabin lighting retuned: warm pooled lamp light, cool porthole rim,
  lamp shadows, dial backlight.
- Procedural stand-ins removed (bulkhead, tanks, consoles, levers,
  indicator columns, placeholder pipe run, dial face PNGs).
- Tests adapted where nodes disappeared; one assertion removed
  (pipe_segment_count) until the pipe kit is placed.
- Model .glb files are committed without LFS; textures Godot extracts
  next to them at import are ignored.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

game/presentation/cockpit/cockpit_mesh_factory.gd

@@ -87,3 +87,27 @@ static func add_sphere(
 	instance.position = position
 	parent.add_child(instance)
 	return instance
+
+
+## Gives an imported mesh instance its own copy of its first surface material,
+## so driving a property (emission) never edits the resource shared by the model.
+static func own_surface_material(instance: MeshInstance3D) -> BaseMaterial3D:
+	if instance == null or instance.mesh == null or instance.mesh.get_surface_count() == 0:
+		return null
+	var shared := instance.mesh.surface_get_material(0) as BaseMaterial3D
+	if shared == null:
+		return null
+	var owned := shared.duplicate() as BaseMaterial3D
+	instance.set_surface_override_material(0, owned)
+	return owned
+
+
+## Stops every mesh under `root` (root included) from casting shadows.
+static func disable_shadow_casting(root: Node) -> void:
+	if root == null:
+		return
+	var meshes: Array[Node] = root.find_children("*", "MeshInstance3D", true, false)
+	meshes.append(root)
+	for node: Node in meshes:
+		if node is MeshInstance3D:
+			(node as MeshInstance3D).cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_OFF