chore: release version 2.3.5 and refactor lobby

Bump export_presets.cfg version to 2.3.5. Update CHANGELOG_DRAFT.md.
Refactor lobby.gd into LobbyChat, LobbyMainMenu, LobbyRoomList, LobbyRoom.
Move Nakama config to environment variables in nakama_manager.gd.
Derive auth_manager.gd encryption key from OS.get_unique_id().sha256_text().
Remove Steam email auth fallback. Require auth ticket.
Make GachaManager.pull() async in gacha_panel.gd.
Remove dummy wallet seeding. Add store_type to IAP payload.
Validate IAP receipts server-side in economy.lua.
Register gacha module in main.lua.
Clean backend_service.gd stubs.
Fix featured_banners type safety in gacha_manager.gd. Guards non-array responses.
Move tiles_armagedon_a1.res to assets/models/meshes/. Fix import fallback_path.

addons/gut/hook_script.gd

@@ -0,0 +1,58 @@
+class_name GutHookScript
+## This script is the base for custom scripts to be used in pre and post
+## run hooks.
+##
+## GUT Wiki:  [url=https://gut.readthedocs.io]https://gut.readthedocs.io[/url]
+## [br][br]
+## Creating a hook script requires that you:[br]
+##  - Inherit [code skip-lint]GutHookScript[/code][br]
+##  - Implement a [code skip-lint]run()[/code] method[br]
+##  - Configure the path in GUT (gutconfig and/or editor) as the approparite hook (pre or post).[br]
+##
+## See [wiki]Hooks[/wiki]
+
+
+## Class responsible for generating xml.  You could use this to generate XML
+## yourself instead of using the built in GUT xml generation options.  See
+## [addons/gut/junit_xml_export.gd]
+var JunitXmlExport = load('res://addons/gut/junit_xml_export.gd')
+
+## This is the instance of [GutMain] that is running the tests.  You can get
+## information about the run from this object.  This is set by GUT when the
+## script is instantiated.
+var gut  = null
+
+# the exit code to be used by gut_cmdln.  See set method.
+var _exit_code = null
+
+var _should_abort =  false
+
+## Virtual method that will be called by GUT after instantiating this script.
+## This is where you put all of your logic.
+func run():
+	gut.logger.error("Run method not overloaded.  Create a 'run()' method in your hook script to run your code.")
+
+## Register inner classes from one or more scripts for doubling.
+## `scripts` may be either a script or an array of scripts.
+## Only worth calling from pre-run hook, not post-run.
+func register_inner_classes(script: Script):
+	gut.get_doubler().inner_class_registry.register(script)
+
+## Set the exit code when running from the command line.  If not set then the
+## default exit code will be returned (0 when no tests fail, 1 when any tests
+## fail).
+func set_exit_code(code : int):
+	_exit_code  = code
+
+## Returns the exit code set with [code skip-lint]set_exit_code[/code]
+func get_exit_code():
+	return _exit_code
+
+## Usable by pre-run script to cause the run to end AFTER the run() method
+## finishes.  GUT will quit and post-run script will not be ran.
+func abort():
+	_should_abort = true
+
+## Returns if [code skip-lint]abort[/code] was called.
+func should_abort():
+	return _should_abort