fix: auto-build UI containers for Bitcoin, LND, Electrumx

Critical: headless services (Bitcoin, LND, Electrumx) need companion
UI containers that serve web dashboards. These were only built for
Bitcoin, and only on bundled ISO builds.

Changes:
- install.rs: auto-build UI containers for LND (port 8081) and
  Electrumx (port 50002) in addition to Bitcoin (port 8334)
- build-auto-installer-iso.sh: always bundle docker UI source files
  (was skipping for unbundled builds — they're tiny HTML, not images)
- Dockerfiles: fix nginx base image tag 1.29.6→1.27.4 (matches registry)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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

@@ -615,31 +615,54 @@ printtoconsole=1\n",
             });
         }
 
-        if matches!(package_id, "bitcoin" | "bitcoin-core" | "bitcoin-knots") {
+        // Build and start companion UI containers for headless services
+        let ui_builds: Vec<(&str, &str, &str, &str)> = match package_id {
+            "bitcoin" | "bitcoin-core" | "bitcoin-knots" => {
+                vec![("bitcoin-ui", "/opt/archipelago/docker/bitcoin-ui", "localhost/bitcoin-ui", "8334:80")]
+            }
+            "lnd" => {
+                vec![("archy-lnd-ui", "/opt/archipelago/docker/lnd-ui", "localhost/lnd-ui", "8081:80")]
+            }
+            "electrumx" | "electrs" | "mempool-electrs" => {
+                vec![("archy-electrs-ui", "/opt/archipelago/docker/electrs-ui", "localhost/electrs-ui", "50002:80")]
+            }
+            _ => vec![],
+        };
+
+        for (name, ui_dir, image, port) in ui_builds {
+            let name = name.to_string();
+            let ui_dir = ui_dir.to_string();
+            let image = image.to_string();
+            let port = port.to_string();
             tokio::spawn(async move {
-                let ui_dir = "/opt/archipelago/docker/bitcoin-ui";
+                if !std::path::Path::new(&ui_dir).exists() {
+                    info!("UI source not found at {}, skipping", ui_dir);
+                    return;
+                }
+                info!("Building UI container {} from {}", name, ui_dir);
                 let _ = tokio::process::Command::new("podman")
-                    .args(["build", "-t", "localhost/bitcoin-ui", ui_dir])
+                    .args(["build", "-t", &image, &ui_dir])
                     .output()
                     .await;
                 let _ = tokio::process::Command::new("podman")
-                    .args(["rm", "-f", "bitcoin-ui"])
+                    .args(["rm", "-f", &name])
                     .output()
                     .await;
                 let _ = tokio::process::Command::new("podman")
                     .args([
-                        "run",
-                        "-d",
-                        "--name",
-                        "bitcoin-ui",
+                        "run", "-d",
+                        "--name", &name,
                         "--restart=unless-stopped",
-                        "-p",
-                        "8334:80",
-                        "localhost/bitcoin-ui:latest",
+                        "--network=archy-net",
+                        "--cap-drop=ALL",
+                        "--cap-add=NET_BIND_SERVICE",
+                        "--memory=64m",
+                        "-p", &port,
+                        &format!("{}:latest", image),
                     ])
                     .output()
                     .await;
-                info!("Bitcoin UI container started on port 8334");
+                info!("{} UI container started on port {}", name, port);
             });
         }
     }