Initial commit: SpaceshipTest, a top-down space RTS in Godot 4.7.1

A fleet of neon-outlined ships explores a procedurally generated, seeded
infinite world: tap/joystick steering, pinch zoom, formation pivoting,
planet landings, an ore economy with extractors and haulers, and player
built structures (mothership, ship crafter, command centre).

All art is hand-drawn with draw_* calls rather than textures, and the
backgrounds are camera-relative shaders so they stay precise at large
world coordinates.

Includes a 35-test headless suite (tests/run_tests.sh) plus screenshot
tooling that renders real frames through Xvfb and Mesa softpipe, since
--headless has no GPU.

Excluded from version control: .godot/ (import cache, and it holds
export credentials), builds/, android/build/ and packaged APKs - all
regenerable, and ~325 MB combined.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/_build_popup_preview.gd

@@ -0,0 +1,31 @@
+extends Node2D
+
+# Preview scene - NOT run by run_tests.sh (underscore prefix). Opens the
+# build menu and shows a building's info popup, so the panel layout can be
+# checked with real text in it. Uses the mothership-already-exists case on
+# purpose: that is the longest message any option produces, so if it fits,
+# the others do.
+#
+#   bash tests/screenshot.sh res://tests/_build_popup_preview.tscn /tmp/out.png 40
+
+
+const SHOW_POPUP: bool = true
+
+
+func _ready() -> void:
+	GameState.buildings.clear()
+	GameState.extractors.clear()
+	GameState.rocks = 500
+	GameState.add_building(GameState.BUILDING_MOTHERSHIP, Vector2(-900.0, 0.0))
+
+	var main: Node = load("res://Main.tscn").instantiate()
+	add_child(main)
+	main.get_node("AsteroidField").set_process(false)
+	main.get_node("EnemySpawner").set_process(false)
+
+	var controller: Node = main.get_node("BuildController")
+	controller._on_build_pressed()
+	# Flip SHOW_POPUP to check the menu underneath
+	# instead of the popup that covers it.
+	if SHOW_POPUP:
+		controller._on_place_mothership()