Follow rubbs to the engines org

The gem source still pointed at the legacy git.teletype.hu host and the
old tools org. The pinned revision is unchanged — only the remote moved.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Gemfile

@@ -1,3 +1,3 @@
 source 'https://rubygems.org'
 
-gem 'bbs', git: 'https://git.teletype.hu/tools/rubbs.git'
+gem 'bbs', git: 'https://git.teletypegames.org/engines/rubbs.git'

Gemfile.lock

@@ -1,5 +1,5 @@
 GIT
-  remote: https://git.teletype.hu/tools/rubbs.git
+  remote: https://git.teletypegames.org/engines/rubbs.git
   revision: 6b320318ca056e17c4fa0890ed0ca977438fe00a
   specs:
     bbs (0.4.0)