fix(install): mesh app-port relay no longer kills the daemon on install

The v6 app-port relay preemptively bound [::]:<port> for ALL catalog
ports, even apps not installed. Installing such an app (grafana:3000,
photoprism, uptime-kuma, jellyfin — framework-pt 2026-07-27) then hit
'address already in use' from the relay, which triggered
cleanup_stale_pasta_port ->  -> killed archipelago
itself (it held the port) mid-install. The daemon crash-looped and the
half-created apps were rolled back and vanished.

Two fixes:
- relay only bridges a port that a running app already answers on over
  IPv4 (probe 127.0.0.1:port first) — an uninstalled app's port is never
  held, so its install sees a free port and never triggers the cleanup.
- cleanup_stale_pasta_port excludes our own PID from both the ss-based
  kill and the fuser kill, so freeing a port can never terminate the
  daemon even when the relay legitimately holds it (reinstall case).

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

core/archipelago/src/api/rpc/package/install.rs

@@ -2324,17 +2324,28 @@ async fn cleanup_start_conflict(package_id: &str, stderr: &str) -> bool {
 }
 
 async fn cleanup_stale_pasta_port(port: &str) {
+    // NEVER kill our own process. The daemon holds catalog app ports over
+    // IPv6 (the mesh app-port relay), so a blunt `fuser -k <port>/tcp` would
+    // terminate archipelago itself mid-install — installs failed and apps
+    // vanished on framework-pt 2026-07-27. Kill every listener on the port
+    // EXCEPT our PID (and our process group), leaving the relay/daemon alive.
+    let self_pid = std::process::id();
     let kill_listener = format!(
-        "ss -ltnp 'sport = :{}' 2>/dev/null | sed -n 's/.*pid=\\([0-9]*\\).*/\\1/p' | xargs -r kill 2>/dev/null || true",
-        port
+        "ss -ltnp 'sport = :{port}' 2>/dev/null | sed -n 's/.*pid=\\([0-9]*\\).*/\\1/p' | \
+         while read p; do [ \"$p\" = \"{self_pid}\" ] || kill \"$p\" 2>/dev/null; done || true",
     );
     let _ = tokio::process::Command::new("sh")
         .args(["-c", &kill_listener])
         .output()
         .await;
 
-    let _ = tokio::process::Command::new("sudo")
-        .args(["fuser", "-k", &format!("{}/tcp", port)])
+    // sudo fuser -k, but exclude our own PID: fuser prints the PIDs holding
+    // the port; kill each except self. (`fuser -k` has no exclusion flag.)
+    let fuser_kill = format!(
+        "for p in $(sudo fuser {port}/tcp 2>/dev/null); do [ \"$p\" = \"{self_pid}\" ] || sudo kill \"$p\" 2>/dev/null; done || true",
+    );
+    let _ = tokio::process::Command::new("sh")
+        .args(["-c", &fuser_kill])
         .output()
         .await;
 

core/archipelago/src/server.rs

@@ -1103,12 +1103,32 @@ async fn app_port_v6_relay_loop(mut shutdown_rx: tokio::sync::watch::Receiver<bo
                     if bridged.contains(&port) {
                         continue;
                     }
+                    // ONLY bridge a port that a running app already answers on
+                    // over IPv4. Binding [::]:port for an app that isn't
+                    // installed is actively harmful: it makes that app's
+                    // later install hit "address already in use", and the
+                    // install's port-free step (`fuser -k <port>/tcp`) then
+                    // kills THIS daemon, which holds the port — the exact
+                    // cause of installs failing + apps vanishing on
+                    // framework-pt 2026-07-27. No v4 listener → skip; the
+                    // next rescan picks it up once the app is up.
+                    let v4_up = tokio::time::timeout(
+                        std::time::Duration::from_millis(300),
+                        tokio::net::TcpStream::connect(("127.0.0.1", port)),
+                    )
+                    .await
+                    .ok()
+                    .and_then(|r| r.ok())
+                    .is_some();
+                    if !v4_up {
+                        continue;
+                    }
                     let addr = SocketAddr::new(
                         std::net::IpAddr::V6(std::net::Ipv6Addr::UNSPECIFIED),
                         port,
                     );
-                    // EADDRINUSE = the app itself (or a prior relay) already
-                    // answers on v6 — exactly when we must stay out of the way.
+                    // EADDRINUSE = the app itself already answers on v6 —
+                    // exactly when we must stay out of the way.
                     let Ok(listener) = bind_v6_only(addr) else { continue };
                     bridged.insert(port);
                     debug!("v6 relay bridging [::]:{port} -> 127.0.0.1:{port}");