fix(downloader): use proper atomic ordering for thread-safe progress tracking

Replace Ordering::Relaxed with appropriate synchronization:
- Ordering::AcqRel for fetch_add operations that modify shared state
- Ordering::Acquire for loads that depend on other thread's writes
- Ordering::Release for stores that other threads may read

This ensures visibility of downloaded bytes and completed files across
concurrent download tasks without data races.

0 files changed, 0 insertions, 0 deletions