Fix Helm chart: rename minio.ingress to minioIngress to avoid subchart conflict (#48)

- Renamed minio.ingress to minioIngress to avoid collision with Bitnami MinIO subchart
- Updated minio-ingress.yaml template to use new key
- Updated _helpers.tpl to use new key
- Updated README documentation

CHANGELOG.md

@@ -13,7 +13,7 @@ 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 `minioIngress` config in Helm chart for exposing MinIO 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)