fix(security): FIPS v6 relay hands gated ports to the app gate

The mesh relay is a raw unauthenticated forward to the app's loopback,
and whether it or the gate owned a fips0 ULA port was decided by a bind
race — the dev box happened to be safe because the gate bound first.
The relay now skips ports declared auth: gated and tears down any
existing bridge for a port that became gated since it was bridged
(catalog refresh), releasing the bind for the gate's next sweep.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

core/archipelago/src/server.rs

@@ -1145,16 +1145,37 @@ fn fips_app_relay_addr(ip: std::net::Ipv6Addr, port: u16) -> SocketAddr {
 /// without a daemon restart. Each relay binds to the fips0 ULA only and
 /// forwards raw TCP to the same port on IPv4 loopback.
 async fn app_port_v6_relay_loop(mut shutdown_rx: tokio::sync::watch::Receiver<bool>) {
-    use std::collections::HashSet;
-    let mut bridged: HashSet<u16> = HashSet::new();
+    use std::collections::HashMap;
+    let mut bridged: HashMap<u16, tokio::task::JoinHandle<()>> = HashMap::new();
     let mut interval = tokio::time::interval(std::time::Duration::from_secs(60));
     interval.set_missed_tick_behavior(tokio::time::MissedTickBehavior::Delay);
     loop {
         tokio::select! {
             _ = interval.tick() => {
                 let Some(fips_ip) = crate::fips::iface::fips0_ula() else { continue };
+                // Ports declared `auth: gated` belong to the app gate on the
+                // fips0 ULA. This relay is a raw unauthenticated forward to
+                // the app's loopback, so bridging a gated port would bypass
+                // the gate — and which of the two wins the bind used to be a
+                // race. Skip them here, and tear down any bridge for a port
+                // that became gated since it was bridged (catalog refresh),
+                // releasing the bind so the gate's next sweep claims it.
+                let gated: std::collections::HashSet<u16> = crate::appgate::identity::build_port_map()
+                    .gated_ports()
+                    .map(|g| g.port)
+                    .collect();
                 for &port in crate::fips::app_ports::APP_LAUNCH_PORTS {
-                    if bridged.contains(&port) {
+                    if gated.contains(&port) {
+                        if let Some(handle) = bridged.remove(&port) {
+                            handle.abort();
+                            info!(
+                                port,
+                                "v6 relay released a bridge: port is now gate-owned"
+                            );
+                        }
+                        continue;
+                    }
+                    if bridged.contains_key(&port) {
                         continue;
                     }
                     // ONLY bridge a port that a running app already answers on
@@ -1181,10 +1202,9 @@ async fn app_port_v6_relay_loop(mut shutdown_rx: tokio::sync::watch::Receiver<bo
                     // EADDRINUSE = fipsd or another process already answers
                     // on this mesh address/port, so stay out of the way.
                     let Ok(listener) = bind_v6_only(addr) else { continue };
-                    bridged.insert(port);
                     debug!("v6 relay bridging [{fips_ip}]:{port} -> 127.0.0.1:{port}");
                     let mut rx = shutdown_rx.clone();
-                    tokio::spawn(async move {
+                    let handle = tokio::spawn(async move {
                         loop {
                             tokio::select! {
                                 accepted = listener.accept() => {
@@ -1205,6 +1225,7 @@ async fn app_port_v6_relay_loop(mut shutdown_rx: tokio::sync::watch::Receiver<bo
                             }
                         }
                     });
+                    bridged.insert(port, handle);
                 }
             }
             _ = shutdown_rx.changed() => return,