Change nickname validation to match classic launcher

lib/common.rb

@@ -61,10 +61,8 @@ class W3DHub
       prefill: Store.settings[:server_list_username],
       accept_callback: accept_callback,
       cancel_callback: cancel_callback,
-          # See: https://gitlab.com/danpaul88/brenbot/-/blob/master/Source/renlog.pm#L136-175
       valid_callback: proc do |entry|
-            entry.length > 1 && entry.length < 30 && (entry =~ /(:|!|&|%| )/i).nil? &&
-              (entry =~ /[\001\002\037]/).nil? && (entry =~ /\\/).nil?
+        entry.length.between?(3, 40) && (entry =~ /^[a-z0-9_\-\[\]]+$/i)
       end
     )
   end
@@ -123,7 +121,6 @@ class W3DHub
       process_info = Process.create(**hash)
 
       pid = process_info.process_id
-      status = -1
 
       until (status = Process.get_exitcode(pid))
         if block