fix(frontend): middleware rewrites remote actor URLs to avoid Next.js file-extension routing issue

thoughts-frontend/middleware.ts

@@ -0,0 +1,23 @@
+import { NextResponse } from "next/server";
+import type { NextRequest } from "next/server";
+
+export function middleware(request: NextRequest) {
+  const parts = request.nextUrl.pathname.split("/");
+
+  // /users/@user@instance or /users/%40user%40instance
+  if (parts.length === 3 && parts[1] === "users") {
+    const decoded = decodeURIComponent(parts[2]);
+    if (decoded.startsWith("@") && decoded.indexOf("@", 1) !== -1) {
+      const url = request.nextUrl.clone();
+      url.pathname = "/remote-actor";
+      url.searchParams.set("handle", decoded);
+      return NextResponse.rewrite(url);
+    }
+  }
+
+  return NextResponse.next();
+}
+
+export const config = {
+  matcher: "/users/:path*",
+};