add configurable firewall host IP for firewall command generation

static/app.js

@@ -6,14 +6,31 @@ document.addEventListener('DOMContentLoaded', () => {
     const ufwCmd = document.getElementById('ufw-cmd');
     const iptablesCmd = document.getElementById('iptables-cmd');
 
+    let config = { firewall_host_ip: null };
+
     const updateFirewallCmds = () => {
         const port = portInput.value || '4646';
-        const hostIp = window.location.hostname;
+        const hostIp = config.firewall_host_ip || window.location.hostname;
         ufwCmd.textContent = `sudo ufw allow from ${hostIp} to any port ${port} proto tcp`;
         iptablesCmd.textContent = `sudo iptables -I INPUT -p tcp -s ${hostIp} --dport ${port} -j ACCEPT`;
     };
 
+    const fetchConfig = async () => {
+        try {
+            const res = await fetch('/api/config');
+            if (res.ok) {
+                config = await res.json();
+                updateFirewallCmds();
+            }
+        } catch (e) {
+            console.error('Failed to fetch config:', e);
+        }
+    };
+
     portInput.addEventListener('input', updateFirewallCmds);
+    
+    // Initial fetch of config and instances
+    fetchConfig();
     updateFirewallCmds();
 
     const fetchInstances = async () => {