The concurrent upload tests were hardcoding localhost:8080 for worker
threads, but CI sets ORCHARD_TEST_URL to the actual server hostname.
This caused "Connection refused" errors in CI.
- Add proxy-body-size annotation to allow unlimited uploads via nginx
- Add requires_direct_s3 marker for tests needing direct MinIO access
- Exclude requires_direct_s3 tests from CI (can't access MinIO from outside K8s)
- Add auto-migration for tag ref_count triggers to ensure they exist