Share one backdrop between game and editor, and fix three input/economy bugs

The setup editor and the landed surface drew different backgrounds for the
same planet. Each scene carried its own hand-written ShaderMaterial, and only
the game side ever swapped in a profile's shader, so a gas giant authored in
the editor showed recoloured craters while the game showed cloud bands. Both
now instance one SurfaceBackground.tscn and configure it through one method,
and every profile names its own shader - the old "null means keep whatever
the scene already had" convention was the drift, since each scene "already
had" something different. The shared material is resource_local_to_scene, or
two live surfaces would repaint each other.

The gas giant's bands broke into disjoint segments once per cell: the second
turbulence octave doubled only the INTEGER half of a lattice coordinate,
which is a different point in every cell rather than the same point at twice
the frequency. Measured, the old form steps 0.153 at a cell boundary against
0.0002 now. A second discontinuity went with it - the camera cell index
arrives pre-wrapped, so hashing it raw rearranged the whole sky every 32
cells; hashes are now wrapped per octave and the field is exactly periodic.
Bands also gained low-frequency octaves and per-row differential drift.

WorldMap swallowed every touch in _input(), which runs before the GUI system,
so CloseButton never saw one: the map could be opened and not closed. Android
and desktop hid it behind Godot's emulated mouse event, which this never
swallowed; a phone browser gives no such second chance. Its test had been
closing the map by calling the method the button was failing to reach.

Construction now draws on the fleet hold as well as the bank. With an empty
starting bank and ore bankable only at a mothership, charging construction to
the bank alone made the first mothership cost ore that could not yet exist.

Also: a conquered planet no longer re-spawns its garrison (guarded on having
capture points, since a setup with none registers as vacuously conquered);
planets keep the map they drew, with the candidate list sorted rather than
left in filesystem order and assignments pruned rather than cleared on
rescan; and the map editor lists setups at a tappable size and can delete
one, as an explicit armed mode rather than a tap away from destroying work.

Full suite 106/106.

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

PlanetSetups.gd

@@ -16,6 +16,8 @@ const PLANET_SETUP_SCRIPT: Script = preload("res://PlanetSetup.gd")
 
 static var _all: Array = []
 static var _scanned: bool = false
+# Which setup each planet drew, once it has drawn one. See setup_for_planet.
+static var _assigned: Dictionary = {}
 
 
 static func _ensure_scanned() -> void:
@@ -42,6 +44,17 @@ static func rescan() -> void:
 	_all = []
 	_scanned = false
 	_ensure_scanned()
+	# Assignments are PRUNED, not cleared. Clearing them would undo the whole
+	# point of remembering: saving one map in the editor would silently re-deal
+	# every planet the player had already visited. What has to go is only the
+	# entries pointing at a setup that no longer exists - a deleted map must
+	# not stay pinned to a planet.
+	var live: Dictionary = {}
+	for setup in _all:
+		live[setup] = true
+	for key in _assigned.keys():
+		if not live.has(_assigned[key]):
+			_assigned.erase(key)
 
 
 static func all() -> Array:
@@ -54,16 +67,41 @@ static func setups_for_profile(profile_id: String) -> Array:
 	for setup in all():
 		if setup.surface_profile_id == profile_id:
 			result.append(setup)
+	# Sorted by id, because the order they arrive in is whatever order the
+	# filesystem listed them in - which is not something to seed a choice
+	# with. The pick below indexes into this array, so an unstable order
+	# means the same planet can land on a different map from one run to the
+	# next, and the "this is MY planet's layout" illusion goes with it.
+	result.sort_custom(func(a, b): return String(a.setup_id) < String(b.setup_id))
 	return result
 
 
 static func setup_for_planet(planet_id: String, profile_id: String) -> Resource:
-	# Same pattern as WorldGen.planet_data_at_chunk: seeded purely from the
-	# planet's own stable id, so the same planet always resolves to the
-	# same setup from anywhere, with nothing stored.
+	# Every planet gets a map of its own type, drawn at random, and keeps it.
+	#
+	# The draw is seeded purely from the planet's own stable id - same pattern
+	# as WorldGen.planet_data_at_chunk - so leaving a planet and coming back
+	# lands on the same layout without anything having to be saved.
+	#
+	# The result is then remembered anyway, because the seed alone is not
+	# quite enough: the pool it indexes into changes the moment the map editor
+	# saves a new setup, which would silently re-deal every planet in the
+	# middle of a session. Once a planet has been visited its map is pinned
+	# for as long as the process lives.
+	#
+	# Keyed on the profile too, not the planet alone: the memo must never be
+	# able to hand back a gas map for a rocky query just because that planet
+	# id was seen first.
+	var key: String = "%s|%s" % [planet_id, profile_id]
+	var remembered: Resource = _assigned.get(key)
+	if remembered != null:
+		return remembered
+
 	var candidates: Array = setups_for_profile(profile_id)
 	if candidates.is_empty():
 		return null
 	var rng: RandomNumberGenerator = RandomNumberGenerator.new()
 	rng.seed = hash(planet_id)
-	return candidates[rng.randi() % candidates.size()]
+	var chosen: Resource = candidates[rng.randi() % candidates.size()]
+	_assigned[key] = chosen
+	return chosen