feat(transfer): apply retention and legal hold atomically

[cxymds]

Closes rustfs/backlog#1460

Background

The transfer option model already carried Object Lock retention and legal-hold state, but the S3 adapter rejected those fields. Applying them after object creation would leave a temporary unlocked version and violate WORM guarantees.

Root cause

Advanced writes had no typed mapping from the core Object Lock model to PutObject, CopyObject, or CreateMultipartUpload, and generic error classification could not distinguish lock configuration, IAM, and policy failures.

Solution

• validate retention expiry before any mutation
• apply retention mode/date and legal hold atomically to PutObject and CopyObject
• apply lock headers exactly once on CreateMultipartUpload, never UploadPart or CompleteMultipartUpload
• classify disabled Object Lock, IAM denial, governance/compliance policy conflicts, and source lookup failures deterministically
• add request-capture coverage plus a RustFS beta.10 smoke test for Put, Copy, multipart persistence, and cleanup
• preserve the #1461 boundary: no cp/pipe flags, output changes, schema changes, or protected documentation changes

Validation

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace
• cargo test -p rustfs-cli --test integration --features integration --no-run
• workflow YAML and shell syntax validation

All local checks pass.