fix(s3): preserve list version page missing-bucket errors

[overtrue]

Related issue(s)

Follow-up coverage for the ls --versions work in #162.

Background

The recent ls --versions change introduced S3Client::list_object_versions_page to preserve pagination markers and delete markers for version listings. That helper is the behavior boundary the CLI now relies on.

Root cause

The new helper had no direct regression coverage. When exercised against a NoSuchBucket service response, it still used the raw SDK display string for classification, which drops the AWS error code in this test harness and falls back to Error::General instead of the expected Error::NotFound.

Solution

This change adds focused unit coverage for the version-listing page contract and aligns the helper with the existing S3 error formatting path. The new tests verify that the request carries the versions subresource, prefix, and max-keys parameters, that delete markers and pagination metadata are preserved, and that NoSuchBucket maps back to the bucket-not-found contract.

Validation

• cargo test -p rc-s3 list_object_versions_page --lib
• cargo test -p rustfs-cli ls::tests --lib
• make pre-commit