Add planet setups as authored resources (#42)

PlanetSetup/PlanetSetupSpawn define a curated capture-point/enemy
layout for a surface profile; PlanetSetups scans res://PlanetSetups/
at first use (not a hardcoded preload table) so dropping in a new
.tres is the only step needed to add one, and resolves the same
setup for the same planet deterministically, same pattern as
WorldGen.planet_data_at_chunk. PlanetSurfaceController composes a
PlanetSetupHost onto the landed surface alongside the existing
resource-provider feature scene.

Ships two starter setups (rocky_default, gas_default) with
placeholder capture-point markers; #43 replaces the markers with the
real CapturePoint scene through the same apply_setup() entry point.

Part of the #40 conquest-mechanic breakdown.

tests/test_planet_setups.gd

@@ -0,0 +1,129 @@
+extends SceneTree
+
+# Headless gameplay test: run with
+#   godot --headless -s res://tests/test_planet_setups.gd
+# Verifies:
+#   1. setup_for_planet is deterministic per planet_id and only returns
+#      setups matching the requested surface profile
+#   2. dropping a new .tres into res://PlanetSetups/ makes it appear via
+#      PlanetSetups.rescan() with no other code change
+#   3. landing on a rocky/gas planet composes a PlanetSetupHost carrying the
+#      resolved setup, with one marker per capture point
+
+const SCRATCH_SETUP_PATH: String = "res://PlanetSetups/_test_scratch_setup.tres"
+
+var game_state: Node
+var rocky_setup: Resource
+var stage: int = 0
+var elapsed: float = 0.0
+var pending_surface: Node
+
+
+func _initialize() -> void:
+	# --- 1. determinism and profile filtering ---
+	rocky_setup = PlanetSetups.setup_for_planet("chunk:3:7", "rocky")
+	if rocky_setup == null:
+		return _fail("no rocky setup resolved for a rocky planet id")
+	if rocky_setup.surface_profile_id != "rocky":
+		return _fail("resolved setup does not match the requested profile")
+	var rocky_setup_again: Resource = PlanetSetups.setup_for_planet("chunk:3:7", "rocky")
+	if rocky_setup != rocky_setup_again:
+		return _fail("setup_for_planet was not deterministic for the same planet id")
+
+	var gas_setup: Resource = PlanetSetups.setup_for_planet("chunk:3:7", "gas")
+	if gas_setup == null:
+		return _fail("no gas setup resolved for the same planet id under the gas profile")
+	if gas_setup.surface_profile_id != "gas":
+		return _fail("gas request returned a mismatched-profile setup")
+
+	for setup in PlanetSetups.setups_for_profile("rocky"):
+		if setup.surface_profile_id != "rocky":
+			return _fail("setups_for_profile('rocky') leaked a non-rocky setup")
+
+	# --- 2. dropping a new .tres is picked up by rescan() ---
+	var before_count: int = PlanetSetups.setups_for_profile("rocky").size()
+	var scratch: Resource = PlanetSetup.new()
+	scratch.setup_id = "_test_scratch_setup"
+	scratch.display_name = "Scratch"
+	scratch.surface_profile_id = "rocky"
+	scratch.capture_points = PackedVector2Array([Vector2(100, 100)])
+	var save_err: int = ResourceSaver.save(scratch, SCRATCH_SETUP_PATH)
+	if save_err != OK:
+		return _fail("could not save the scratch setup for the pickup check (err %d)" % save_err)
+	PlanetSetups.rescan()
+	var after_count: int = PlanetSetups.setups_for_profile("rocky").size()
+	DirAccess.remove_absolute(ProjectSettings.globalize_path(SCRATCH_SETUP_PATH))
+	var import_file: String = SCRATCH_SETUP_PATH + ".import"
+	if FileAccess.file_exists(import_file):
+		DirAccess.remove_absolute(ProjectSettings.globalize_path(import_file))
+	PlanetSetups.rescan()
+	if after_count != before_count + 1:
+		return _fail("registry did not pick up a newly saved setup (before=%d after=%d)" % [
+			before_count, after_count
+		])
+
+	# --- 3. landing composes a PlanetSetupHost with the resolved setup ---
+	# Deferred to _process(): a scene instantiated and added to the tree
+	# inside _initialize() has not had its _ready() chain flushed yet (this
+	# runs before the engine's first frame), so children added during
+	# PlanetSurfaceController._ready() are not observable until a frame has
+	# actually processed - see test_gas_system.gd for the same pattern.
+	game_state = root.get_node("GameState")
+	game_state.planet_name = "Setup Test"
+	game_state.planet_id = "chunk:3:7"
+	game_state.planet_definition_id = "rocky"
+	pending_surface = load("res://PlanetSurface.tscn").instantiate()
+	root.add_child(pending_surface)
+
+
+func _process(delta: float) -> bool:
+	elapsed += delta
+	match stage:
+		0:
+			if elapsed < 0.1:
+				return false
+			var host: Node = pending_surface.get_node_or_null("SurfaceFeatures/PlanetSetupHost")
+			if host == null:
+				pending_surface.free()
+				return _fail("landing did not compose a PlanetSetupHost")
+			if host.setup != rocky_setup:
+				pending_surface.free()
+				return _fail("host did not receive the deterministically resolved setup")
+			var marker_count: int = 0
+			for child in host.get_children():
+				if child is NeonPiece:
+					marker_count += 1
+			if marker_count != rocky_setup.capture_points.size():
+				pending_surface.free()
+				return _fail("host placed %d markers for %d capture points" % [
+					marker_count, rocky_setup.capture_points.size()
+				])
+			pending_surface.free()
+
+			game_state.planet_definition_id = "gas_giant"
+			pending_surface = load("res://PlanetSurface.tscn").instantiate()
+			root.add_child(pending_surface)
+			elapsed = 0.0
+			stage = 1
+			return false
+		1:
+			if elapsed < 0.1:
+				return false
+			var gas_host: Node = pending_surface.get_node_or_null("SurfaceFeatures/PlanetSetupHost")
+			if gas_host == null or gas_host.setup.surface_profile_id != "gas":
+				pending_surface.free()
+				return _fail("gas landing did not compose a matching-profile setup host")
+			pending_surface.free()
+
+			print("TEST_PLANET_SETUPS: PASS")
+			quit(0)
+			return true
+	return false
+
+
+func _fail(message: String) -> bool:
+	print("TEST_PLANET_SETUPS: FAIL (%s)" % message)
+	if FileAccess.file_exists(SCRATCH_SETUP_PATH):
+		DirAccess.remove_absolute(ProjectSettings.globalize_path(SCRATCH_SETUP_PATH))
+	quit(1)
+	return true