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_instrument_panel.gd

@@ -12,6 +12,9 @@ const CockpitDetailing = preload(
 const COLOR_NORMAL := Color(0.45, 0.89, 0.90, 1.0)
 const COLOR_ATTENTION := Color(1.0, 0.75, 0.20, 1.0)
 const COLOR_CRITICAL := Color(1.0, 0.42, 0.31, 1.0)
+## 1.0 shows the sonar picture as rendered; slightly above lets its brightest
+## lines bloom without clipping the surface colours.
+const SONAR_SCREEN_ENERGY := 1.25
 
 @onready var _resources_label: Label3D = %ResourcesLabel
 @onready var _navigation_label: Label3D = %NavigationLabel
@@ -84,12 +87,18 @@ func return_text() -> String:
 
 func attach_sonar_texture(texture: Texture2D) -> void:
 	_sonar_texture = texture
+	# The glass shows the picture by emission only: black albedo, no specular,
+	# so cabin lights add nothing to it, and the energy can lift the brightest
+	# lines just above 1.0 for the environment glow to pick up.
 	var material := StandardMaterial3D.new()
-	material.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
-	material.albedo_texture = texture
+	material.albedo_color = Color.BLACK
+	material.metallic_specular = 0.0
+	material.roughness = 1.0
 	material.emission_enabled = true
+	material.emission = Color.WHITE
+	material.emission_operator = BaseMaterial3D.EMISSION_OP_MULTIPLY
 	material.emission_texture = texture
-	material.emission_energy_multiplier = 1.7
+	material.emission_energy_multiplier = SONAR_SCREEN_ENERGY
 	_sonar_screen.material_override = material
 	_sonar_placeholder.visible = false