Browsers were always answerers — meant two browsers in the same room
(no Go peer present) would both wait forever for an offer that no one
would send. Now: on presence from another peer, the browser with the
smaller peerID (lexicographic) initiates the offer; the other side
answers. Tie-break in handleOffer handles the race where both posted
presence simultaneously and could double-offer.
This makes pure-browser meshes work — phone + laptop in the same room
auto-pair without needing a Go peer.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
a0f7498663