Add MinIO ingress support in Helm chart for presigned URLs (#48)

- Add minio.ingress config to values.yaml for exposing MinIO externally
- Create minio-ingress.yaml template for MinIO ingress resource
- Update helpers to use external MinIO URL when ingress is enabled
- Add orchard.download.mode and presignedUrlExpiry to deployment env vars

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added `?mode=` query parameter to override download mode per-request (#48)
 - Added `/api/v1/project/{project}/{package}/+/{ref}/url` endpoint for getting presigned URLs (#48)
 - Added `PresignedUrlResponse` schema with URL, expiry, checksums, and artifact metadata (#48)
+- Added MinIO ingress support in Helm chart for presigned URL access (#48)
+- Added `orchard.download.mode` and `orchard.download.presignedUrlExpiry` Helm values (#48)
 - Added integrity verification workflow design document (#24)
 - Added `sha256` field to API responses for clarity (alias of `id`) (#25)
 - Added `checksum_sha1` field to artifacts table for compatibility (#25)