fix: terminal WebSocket connection timing + better mock fallback

- Fix xterm.js container not found: use requestAnimationFrame retry loop
  instead of single $nextTick (Alpine x-for renders asynchronously)
- Better mock fallback: use host name+IP instead of raw UUID
- Add logging for WebSocket connection path (found/not-found/hostname)

app/backend/internal/handler/terminal.go

@@ -48,10 +48,16 @@ func TerminalWS(c *websocket.Conn) {
 	log.Printf("WS connected: host=%s", hostID)
 
 	host, found := hostStore.Get(hostID)
-	if !found || host.Hostname == "" {
+	if !found {
+		log.Printf("Host %s not found, using mock", hostID)
 		mockTerminal(c, hostID)
 		return
 	}
+	if host.Hostname == "" {
+		log.Printf("Host %s has no hostname, using mock (name=%s, ip=%s)", hostID, host.Name, host.IP)
+		mockTerminal(c, host.Name+" ("+host.IP+")")
+		return
+	}
 
 	client, err := sshconn.Dial(host)
 	if err != nil {