feat(record): capture interactions in embedded frames

Track recording per document so injectable child frames are captured while partial frame failures remain visible in exported traces.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/extension/src/lib/record-document-token.ts

@@ -0,0 +1,24 @@
+/** Attribute written on `<html>` while a document is actively recording. */
+export const RECORD_DOCUMENT_TOKEN_ATTR = "data-bsk-record-document";
+
+export function createRecordDocumentToken(): string {
+  if (typeof crypto !== "undefined" && typeof crypto.randomUUID === "function") {
+    return crypto.randomUUID();
+  }
+  return `doc-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 10)}`;
+}
+
+export function stampRecordDocumentToken(token: string): void {
+  document.documentElement.setAttribute(RECORD_DOCUMENT_TOKEN_ATTR, token);
+}
+
+export function clearRecordDocumentToken(): void {
+  document.documentElement.removeAttribute(RECORD_DOCUMENT_TOKEN_ATTR);
+}
+
+export function readRecordDocumentTokenFromAttrs(
+  attrs: Record<string, string> | undefined,
+): string | undefined {
+  const token = attrs?.[RECORD_DOCUMENT_TOKEN_ATTR];
+  return token?.trim() ? token : undefined;
+}