Compatibility

S3 501 Discipline: Remaining Ops — SelectObjectContent, UploadPartCopy, Analytics, Inventory, Metrics, Intelligent-Tiering

Final 501 sweep: SelectObjectContent, UploadPartCopy, analytics, inventory, metrics, intelligent-tiering now return honest 501 NotImplemented.

S3 501 Discipline: Object-Level Subresources (tagging, acl, versionId, retention, legal-hold)

5 object-level query parameters now return honest 501 NotImplemented instead of silently falling into GetObject/PutObject/DeleteObject.

S3 501 Discipline: Honest 'Not Implemented' for 16 Bucket Config Subresources

16 bucket config subresources (versioning, ACL, policy, CORS, lifecycle, etc.) now return honest 501 NotImplemented instead of silently misrouting to ListObjects/GetObject.