The Launch-local-instances path pinned BT_SELF, which claims a seat
directly and SKIPS the seat request -- the join menu (and the callsign/
mech choice it carries) never ran, so a local test instance couldn't
exercise the walk-up flow. Relay-mode local instances now launch
zero-arg with BT_FE_JOIN=1: the JOIN-GAME menu opens, the relay assigns
the seat, and the choice lands in the egg like any join.bat player.
Each instance gets a distinct relaunch port via BT_FE_JOINPORT
(btl4main JoinRelay case; default 1501) -- two -net listeners can't
share a port on one box. Mesh-mode locals keep the direct path.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
