Uploaded chapters have no source_index, and ORDER BY source_index DESC NULLS
LAST sorted every one of them after all crawled chapters regardless of number
— an uploaded chapter 5 landed after crawled chapter 100. Slot each uploaded
chapter by number, just before the crawled chapter with the smallest greater
number, so it interleaves. Crawled rows keep their reversed source-DOM order,
preserving the deliberate placement of non-numeric entries (migration 0021).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>