Listen on :: (dual-stack) instead of 0.0.0.0

Toes proxy fetches via localhost which may resolve to ::1 on Linux.
Listening on :: accepts both IPv4 and IPv6 connections.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/server.ts

@@ -70,7 +70,7 @@ const websocket = {
 
 const server = Bun.serve({
   port: PORT,
-  hostname: '0.0.0.0',
+  hostname: '::',
   idleTimeout: 255,
 
   fetch(req, server) {