fix(core): mdns fails if service already registered

packages/opencode/src/server/server.ts

@@ -2708,7 +2708,7 @@ export namespace Server {
       opts.hostname !== "localhost" &&
       opts.hostname !== "::1"
     if (shouldPublishMDNS) {
-      MDNS.publish(server.port!)
+      MDNS.publish(server.port!, `opencode-${server.port!}`)
     } else if (opts.mdns) {
       log.warn("mDNS enabled but hostname is loopback; skipping mDNS publish")
     }