Add new AWS checksums

[klauspost]

"Reference": https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity-upload.html

Validated against AWS S3.

[Copilot]

Pull request overview

Adds support for additional checksum algorithms (MD5, SHA-512, XXHash64, XXH3-64, XXH3-128) across the client’s S3 request/response handling and functional validation.

Changes:

• Extend ChecksumType to include MD5/SHA512/XXHash variants and provide hashing/size/header-key support.
• Propagate new checksum fields through object/part data structures and response parsing paths (Put, multipart, list versions, object attributes).
• Expand functional tests to exercise the new checksum types; update example modules to Go 1.25 and add required hashing dependencies.

Reviewed changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
utils.go	Include new checksum headers when building ObjectInfo from response headers.
checksum.go	Add new checksum types, header keys, hashers, raw sizes, and string representations.
api-datatypes.go	Add new checksum fields to UploadInfo and ObjectInfo.
api-s3-datatypes.go	Extend XML datatypes (versions, parts, multipart results) with new checksum fields.
api-get-object-attributes.go	Extend GetObjectAttributes checksum XML fields and mapping helpers.
api-put-object.go	Carry new per-part checksum fields through multipart stream flows.
api-put-object-streaming.go	Carry new per-part checksum fields through streaming multipart flows and PutObject response parsing.
api-put-object-multipart.go	Carry new per-part checksum fields and include them in complete-multipart results.
api-append-object.go	Include new checksum headers in append response parsing.
api-list.go	Populate new checksum fields when listing object versions.
functional_tests.go	Add coverage for the new checksum algorithms in put/streaming/multipart checksum tests.
go.mod	Add xxhash/v2 and zeebo/xxh3 dependencies.
go.sum	Add checksums for new dependencies and transitive modules.
examples/s3/go.mod	Align example module to Go 1.25.
examples/minio/go.mod	Align example module to Go 1.25.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[klauspost]

Obviously running mint fails since it tests against old minio version.

[harshavardhana]

@klauspost we can skip the error in the test if we get "invalid checksum" we can skip the test since this test is downloading OSS minio

[klauspost]

Yeah. We have more tests on the server side, so it wouldn't be too much of a loss. I guess we can deal with scenarios like this later.

[klauspost]

@harshavardhana Ignoring "InvalidArgument" specifically. Added a const we can flip later if we start testing on "AIStor Free".