The server never proactively offered GMCP or MSDP to clients, so
telnetlib3 logged "cannot send MSDP without negotiation" every second.
Now the server sends WILL GMCP and WILL MSDP on connection, and
send_msdp_vitals checks negotiation state before attempting to send.
V5+ games write room names to the upper window (status line) via
select_window(1). Since select_window was a no-op, status line text
leaked into the main output buffer, causing ">Outside" on prompt lines.
Track the active window and only buffer writes to window 0 (lower).
Replaces the async _do_restore() (called after thread launch) with a
synchronous _try_restore() called before the thread starts. This
eliminates the race condition where restore mutates z-machine state
while the interpreter thread is running.
The restore prefix message is now part of start()'s return value
instead of being sent separately in play.py.
Unit tests for MUD UI components (screen, input stream, filesystem)
and integration tests with real zork1.z3 (session lifecycle, escape
commands, save/restore round-trip, state inspection).
