fix: resolve Next.js docker build endpoints and handle async map icons

frontend/src/lib/api.ts

@@ -1 +1,28 @@
-export const API_BASE = process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000";
+// NEXT_PUBLIC_* vars are baked at build time in Next.js, so setting them
+// in docker-compose `environment` has no effect at runtime.  Instead we
+// auto-detect: use the browser's current hostname with a configurable port
+// so the dashboard works on localhost, LAN IPs, and custom Docker port maps
+// without any code changes.
+//
+// Override order:
+//   1. Build-time NEXT_PUBLIC_API_URL (for advanced users who rebuild the image)
+//   2. Runtime auto-detect from window.location.hostname + port 8000
+
+function resolveApiBase(): string {
+  // Build-time override (works when image is rebuilt with the env var)
+  if (process.env.NEXT_PUBLIC_API_URL) {
+    return process.env.NEXT_PUBLIC_API_URL;
+  }
+
+  // Server-side rendering: fall back to localhost
+  if (typeof window === "undefined") {
+    return "http://localhost:8000";
+  }
+
+  // Client-side: use the same hostname the user is browsing on
+  const proto = window.location.protocol;
+  const host = window.location.hostname;
+  return `${proto}//${host}:8000`;
+}
+
+export const API_BASE = resolveApiBase();