style: apply gdformat formatting across the entire project

Auto-format all GDScript files using gdformat from gdtoolkit.
This is a baseline formatting pass to ensure consistent style:

- Normalizes indentation and spacing
- Wraps long lines to 100 characters
- Removes trailing whitespace
- Standardizes blank lines between functions

68 files reformatted, 8 files left unchanged (3rd-party addon files
with parse errors excluded).

tests/save_slot_persistence_test.gd

@@ -2,9 +2,11 @@ extends SceneTree
 
 var failures: Array[String] = []
 
+
 func _initialize() -> void:
 	call_deferred("_run")
 
+
 func _run() -> void:
 	var test_directory := "user://save_slot_test_%s" % Time.get_ticks_usec()
 	var store := SaveSlotStore.new(test_directory)
@@ -48,17 +50,14 @@ func _run() -> void:
 
 	var unchanged_checksum: String = manager.get_state_checksum()
 	var file := FileAccess.open(final_path, FileAccess.WRITE)
-	file.store_string("{\"schema\":\"broken\"}")
+	file.store_string('{"schema":"broken"}')
 	file.close()
 	_check(not store.load_into(manager), "Invalid save data should be rejected")
 	_check(
 		manager.get_state_checksum() == unchanged_checksum,
 		"A rejected save must not partially mutate the simulation"
 	)
-	_check(
-		not store.save(manager, "../escape"),
-		"Slot names must not escape the save directory"
-	)
+	_check(not store.save(manager, "../escape"), "Slot names must not escape the save directory")
 
 	store.delete_slot()
 	DirAccess.remove_absolute(ProjectSettings.globalize_path(test_directory))
@@ -70,6 +69,7 @@ func _run() -> void:
 		push_error("[TEST] " + failure)
 	quit(1)
 
+
 func _check(condition: bool, message: String) -> void:
 	if not condition:
 		failures.append(message)