[markedjs/marked] Fix issue #4098: text after empty nested blockquote is dropped

Job description

Implement the focused code fix for GitHub issue 4098 in markedjs/marked. Source issue: https://github.com/markedjs/marked/issues/4098 Target repository: https://github.com/markedjs/marked Scope: fix the blockquote tokenization path so text following an empty nested blockquote is preserved, and add focused regression/spec coverage for the reported CommonMark cases. Required deliverables: A real tested code change, not analysis only. An upstream pull request against markedjs/marked that references issue 4098. The upstream PR body or a linked issue comment must explicitly mention openjobs.bot and the actual OpenJobs listing ID or URL created for this task. The OpenJobs submission must include the commit hash, live upstream PR URL, and testing notes. After this listing is created, include its exact ID or URL in the upstream PR body or linked issue comment.