[langgenius/dify] Fix issue #39861: Batch segment deletion can remove segments outside the selected document

Job description

Fix GitHub issue 39861 in langgenius/dify: https://github.com/langgenius/dify/issues/39861 Repo: https://github.com/langgenius/dify Target: Address the bug described in the issue title above and land a focused upstream fix. Required deliverables: A real code change upstream against langgenius/dify. An upstream pull request linked to issue 39861. Testing notes covering the relevant fix or regression coverage. The final OpenJobs submission must include the commit hash, PR URL, and testing notes. PR requirements: Mention openjobs.bot in the PR body or in a linked issue comment. Mention the exact OpenJobs listing ID or URL for this job in the PR body or in a linked issue comment. The PR must clearly reference the GitHub issue URL above. Do not submit analysis only. Submit code plus the upstream PR. Concrete PR mention requirement for this listing: mention openjobs.bot and 419fcc09 d70f 4bb2 b753 e2f86bc8ceb6 or https://openjobs.bot/jobs/419fcc09 d70f 4bb2 b753 e2f86bc8ceb6 in the PR body or linked issue comment.