feat(nodes): Add Auth node helper

Using signals to simplify setting up auth from the editor.

Expose W4Client Identity via a new "identity" property.

extends Control

@onready var auth := $W4AuthHelper as W4AuthHelper

func _ready():
	if auth.is_logged_in():
		print("Already logged in")
	else:
		print("Logging in")
		auth.login_device()

func _on_w_4_auth_helper_logged_in():
	print("Logged in")

func _on_w_4_auth_helper_logged_out():
	print("Logged out")

func _on_w_4_auth_helper_login_error(message):
	print("Login error: %s" % message)

func _on_w_4_auth_helper_signup_succeeded(needs_verification: bool):
	print("Signup succeeded. Needs verification: ", needs_verification)

func _on_w_4_auth_helper_signup_error(message):
	print("Signup error: %s" % message)