[codex] fix xiaohongshu download image order

[Scofy0123]

Summary

• Fixes [Bug] xiaohongshu download may save carousel images in DOM order instead of display order #1514
• Prefer Xiaohongshu page-state image arrays when extracting note media for xiaohongshu download
• Keep the existing DOM selector extraction as a fallback when structured note media is unavailable
• Add a regression test that proves canonical state image order wins over mismatched DOM discovery order

Root Cause

xiaohongshu/download previously collected images from carousel-related DOM selectors and stored them in a Set. That preserved DOM discovery order, not necessarily the order shown in the platform carousel. Hidden slides, preloaded slides, duplicated carousel nodes, or responsive rendering can make the visible cover appear after another DOM image, causing filenames like <noteId>_1.jpg to be misleading.

The shared downloadMedia helper simply names files by the media array index it receives, so the adapter needs to pass media in platform display order.

Validation

• npm run test:adapter -- clis/xiaohongshu/download.test.js
• npm run test:adapter -- clis/xiaohongshu/*.test.js
• npm run typecheck