Backend:
- Composite ORDER BY (created_at DESC, iteration ASC, id ASC) to fix
non-deterministic ordering when multiple messages share same second
- Composite key cursor pagination to avoid missing messages at boundary
Android:
- Fix message duplication: guard loadMoreHistory from firing before
initial scroll completes (isAtTop race → fetchOlderMessages →
cacheMessagesFromApi with different IDs → Room duplicates)
- Add distinctBy(id) at all message assignment points in ViewModel
- cacheMessagesFromApi: skip insert if same ID or same content exists
- Add relative timestamp display on message bubbles
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
renjianbo
e33aa6e0b7
