Fix IPv6 listen default (#470)

Co-authored-by: KK <kk@KKs-Mac-Studio.local>

packages/server/src/config.ts

@@ -1,8 +1,16 @@
 import { resolve } from 'path'
 import { homedir } from 'os'
 
+export function getListenHost(env: Record<string, string | undefined> = process.env): string | undefined {
+  const host = env.BIND_HOST?.trim()
+  return host || undefined
+}
+
 export const config = {
   port: parseInt(process.env.PORT || '8648', 10),
+  // Leave host undefined by default so Node binds to IPv6 when available,
+  // falling back to IPv4 on systems without IPv6 support.
+  host: getListenHost(),
   upstream: process.env.UPSTREAM || 'http://127.0.0.1:8642',
   uploadDir: process.env.UPLOAD_DIR || resolve(homedir(), '.hermes-web-ui', 'upload'),
   dataDir: resolve(__dirname, '..', 'data'),

packages/server/src/index.ts

@@ -102,8 +102,10 @@ export async function bootstrap() {
   console.log('[bootstrap] SPA fallback registered')
 
   // Start server
-  console.log(`[bootstrap] listening on port ${config.port}`)
-  server = app.listen(config.port, '0.0.0.0')
+  console.log(`[bootstrap] listening on ${config.host || 'default host'}:${config.port}`)
+  server = config.host
+    ? app.listen(config.port, config.host)
+    : app.listen(config.port)
   console.log('[bootstrap] app.listen called')
 
   setupTerminalWebSocket(server)