Add developer API, Prometheus metrics, and community links

lib/forum.ts

@@ -0,0 +1,16 @@
+import "server-only";
+import forum from "@/shared/forum.json";
+
+/** Only expose a public HTTPS destination, never embedded credentials. */
+export function forumUrl() {
+  const value = process.env.MINEGEO_FORUM_URL ?? forum.url;
+  if (!value.trim()) return null;
+  try {
+    const url = new URL(value.trim());
+    if (url.protocol !== "https:" || url.username || url.password || url.port)
+      return null;
+    return url.href;
+  } catch {
+    return null;
+  }
+}