fix(core): Normalize binary data handling across registries and add buffer helpers

ts/core/helpers.buffer.ts

@@ -0,0 +1,34 @@
+/**
+ * Shared buffer utilities for consistent binary data handling across all registry types.
+ *
+ * This module addresses the common issue where `Buffer.isBuffer(Uint8Array)` returns `false`,
+ * which can cause data handling bugs when binary data arrives as Uint8Array instead of Buffer.
+ */
+
+/**
+ * Check if value is binary data (Buffer or Uint8Array)
+ */
+export function isBinaryData(value: unknown): value is Buffer | Uint8Array {
+  return Buffer.isBuffer(value) || value instanceof Uint8Array;
+}
+
+/**
+ * Convert any binary-like data to Buffer.
+ * Handles Buffer, Uint8Array, string, and objects.
+ *
+ * @param data - The data to convert to Buffer
+ * @returns A Buffer containing the data
+ */
+export function toBuffer(data: unknown): Buffer {
+  if (Buffer.isBuffer(data)) {
+    return data;
+  }
+  if (data instanceof Uint8Array) {
+    return Buffer.from(data);
+  }
+  if (typeof data === 'string') {
+    return Buffer.from(data, 'utf-8');
+  }
+  // Fallback: serialize object to JSON
+  return Buffer.from(JSON.stringify(data));
+}