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>

Starfield.gd

@@ -0,0 +1,28 @@
+extends ColorRect
+
+# Feeds the starfield shader the camera's position split into a CELL INDEX
+# plus a fraction within that cell, rather than a raw world position.
+#
+# Why: the fleet routinely reaches world coordinates in the tens of
+# thousands. Handing those straight to the shader forces every downstream
+# calculation (the division by cell_size, floor/fract, and especially the
+# hash's internal multiplies) to work at large magnitudes, where a mobile
+# GPU's float precision starts to break down - and no precision qualifier
+# can fix that, since `highp` widens the type but the magnitudes stay huge.
+# GDScript computes in double precision, so doing the split here and passing
+# only small numbers (cell indices in the hundreds, fractions in [0,1])
+# keeps the shader's arithmetic in a range it can represent exactly.
+
+@onready var camera: Camera2D = get_node("../../Camera2D")
+
+
+func _process(_delta: float) -> void:
+	var viewport_size: Vector2 = get_viewport_rect().size
+	var cell_size: float = material.get_shader_parameter("cell_size")
+	var p: Vector2 = camera.global_position / cell_size
+	var cell: Vector2 = Vector2(floor(p.x), floor(p.y))
+
+	material.set_shader_parameter("camera_cell", cell)
+	material.set_shader_parameter("camera_frac", p - cell)
+	material.set_shader_parameter("camera_zoom", 1.0 / camera.zoom.x)
+	material.set_shader_parameter("viewport_size", viewport_size)