Host keeps authority as before; a dedicated server (no host player) hands
start/end authority to the first connecting client and reassigns it if that
client leaves. The Start Match trigger now polls a server-side physics overlap
instead of relying on OnTriggerEnter, so it fires for the authority client's
remote avatar (moved by NetworkTransform, no CharacterController.Move on the
server) as well as the host's owned avatar. Esc-to-end routes a named message
from the authority client to the server when that client is not the host.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>