Harden CMS security and theme contrast

src/lib/form-data.ts

@@ -0,0 +1,6 @@
+import { positiveBigInt } from "@/lib/api";
+
+export function formPositiveBigInt(formData: FormData, field: string): bigint | null {
+  const value = formData.get(field);
+  return typeof value === "string" ? positiveBigInt(value.trim()) : null;
+}