Initial SERMO-BBS: a telnet PC that boots SERMO-DOS

A rubbs-based telnet server that drops every caller into a simulated PC:
it POSTs, boots, loads SERMO-DOS, and lands at a C:\> prompt. Built-in DOS
commands (VER/DATE/TIME/ECHO/MEM/DIR/CLS/HELP/EXIT) behave; anything else
is routed to Sermo::Oracle as a question — the hook for a future LLM.

Built on rubbs' configurable BBS::FakeOS engine; the whole OS lives in
lib/sermo/dos.rb as a FakeOS.define block, so new character-mode OSes are
added as config files, not engine changes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Gemfile.lock

@@ -0,0 +1,21 @@
+GIT
+  remote: https://git.teletype.hu/tools/rubbs.git
+  revision: 4d38046c7056e0edbad02f7046ce83522124dccd
+  specs:
+    bbs (0.4.0)
+      artii (~> 2.1)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    artii (2.1.2)
+
+PLATFORMS
+  arm64-darwin-22
+  ruby
+
+DEPENDENCIES
+  bbs!
+
+BUNDLED WITH
+   2.5.22