The anonymous share page-fetch tool's positive branch (sanitize via
updatePublicAttachments then jsonToMarkdown before returning to the model) was
untested, so a dropped/reordered sanitizer would ship a comment-mark/raw-
attachment leak with green tests. Add a positive-branch test pinning the
sanitizer call + that markdown derives from sanitized content, and a soft-deleted
test asserting a generic error with no content fetch.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>