- **Post sync optimization**: Clear store immediately when params change to prevent flashing old posts; replace instead of merge on refresh
- **ImageGallery fix**: Use idempotent download option, migrate to Asset.create() API, fix Android file path requirement, ensure proper cleanup
- **UserProfileScreen**: Add ImageGallery for post image viewing with consistent implementation
- **SearchScreen**: Add entrance animation and empty state
- **ChatScreen**: Remove unused state variables (lastSeq, firstSeq, isProgrammaticScrollRef) and dead imports