add configurable extension backend url and login support

surfsense_web/app/verify-token/route.ts

@@ -0,0 +1,25 @@
+import { NextRequest, NextResponse } from "next/server";
+
+const backendBaseUrl = (process.env.INTERNAL_FASTAPI_BACKEND_URL || "http://backend:8000").replace(
+	/\/+$/,
+	""
+);
+
+export async function GET(request: NextRequest) {
+	const response = await fetch(`${backendBaseUrl}/verify-token`, {
+		method: "GET",
+		headers: {
+			Authorization: request.headers.get("authorization") || "",
+			"X-API-Key": request.headers.get("x-api-key") || "",
+		},
+		cache: "no-store",
+	});
+
+	return new NextResponse(response.body, {
+		status: response.status,
+		headers: {
+			"content-type": response.headers.get("content-type") || "application/json",
+			"cache-control": "no-store",
+		},
+	});
+}