fix: default to 0.0.0.0 to fix WSL2 health check failure (#520)

PR #470 changed the default listen host to undefined, letting Node.js
bind to IPv6 :: on systems that support it. This broke WSL2 where IPv6
dual-stack is unreliable — the server binds to :: but IPv4 127.0.0.1
connections fail, causing the health check to time out.

Revert to 0.0.0.0 as the default. Users who need IPv6 can set
BIND_HOST=:: explicitly.

Fixes #518

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

packages/server/src/routes/hermes/terminal.ts

@@ -110,7 +110,7 @@ function createSession(shell: string): PtySession {
 
 // ─── WebSocket server setup ─────────────────────────────────────
 
-export function setupTerminalWebSocket(httpServer: HttpServer) {
+export function setupTerminalWebSocket(httpServers: HttpServer | HttpServer[]) {
   if (!pty) {
     logger.warn('node-pty not available, skipping terminal WebSocket setup')
     return
@@ -118,26 +118,29 @@ export function setupTerminalWebSocket(httpServer: HttpServer) {
 
   const wss = new WebSocketServer({ noServer: true })
   const defaultShell = findShell()
+  const servers = Array.isArray(httpServers) ? httpServers : [httpServers]
 
-  httpServer.on('upgrade', async (req, socket, head) => {
-    const url = new URL(req.url || '', `http://${req.headers.host}`)
-    if (url.pathname !== '/api/hermes/terminal') {
-      return
-    }
-
-    // Auth check
-    const authToken = await getToken()
-    if (authToken) {
-      const token = url.searchParams.get('token') || ''
-      if (token !== authToken) {
-        socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n')
-        socket.destroy()
+  servers.forEach((httpServer) => {
+    httpServer.on('upgrade', async (req, socket, head) => {
+      const url = new URL(req.url || '', `http://${req.headers.host}`)
+      if (url.pathname !== '/api/hermes/terminal') {
         return
       }
-    }
 
-    wss.handleUpgrade(req, socket, head, (ws) => {
-      wss.emit('connection', ws, req)
+      // Auth check
+      const authToken = await getToken()
+      if (authToken) {
+        const token = url.searchParams.get('token') || ''
+        if (token !== authToken) {
+          socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n')
+          socket.destroy()
+          return
+        }
+      }
+
+      wss.handleUpgrade(req, socket, head, (ws) => {
+        wss.emit('connection', ws, req)
+      })
     })
   })