Sync public snapshot from freebuff-private

Source: CodebuffAI/freebuff-private@04c30f9c322364fb2bf3036212be32dc40245b76

Author: github-actions[bot]

common/src/util/mirror-request.ts

@@ -0,0 +1,11 @@
+import { Buffer } from 'node:buffer'
+
+/** Chat text is data, but Render's WAF can mistake it for executable commands.
+ * The mirror server unwraps this UTF-8 JSON envelope after authentication.
+ * This is transport encoding, not encryption. Deploy the decoder first. */
+export function encodeMirrorRequest(body: unknown): string {
+  return JSON.stringify({
+    encoding: 'base64',
+    data: Buffer.from(JSON.stringify(body), 'utf8').toString('base64'),
+  })
+}