Every offline Horizon player joined as Player, the LAN host's own offline
profile, so the host refused every guest with "You logged in from another
location". Vanilla's client defaults --username to Player + millis % 1000
and the launcher passes the account's name. Horizon now generates
Player + five digits once and keeps it in horizon-player.txt next to
options.txt (same name, same offline UUID, same inventory on a friend's
world). --name, HORIZON_PLAYER_NAME and a signed-in account still win.
tools/test_lan_lifecycle.py: two default guests join one host together,
keep their names across rejoins, and a guest named Player is refused.
Fixes#195
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ludovic Marie
rdbtCVS