fix(ls): honor --versions listings

[overtrue]

Summary

• fix rc ls --versions to list object versions instead of falling back to the normal object listing path
• keep JSON output under the existing items envelope and include version metadata for each returned entry
• add an integration regression test that uploads two versions of the same object and verifies both are returned

Related Issue

• Closes rc does not support displaying multiple versions. #159

Root Cause

LsArgs exposed --versions, but crates/cli/src/commands/ls.rs never used the flag and always called the regular object listing path.

Validation

• cargo fmt --all --check
• cargo clippy --workspace -- -D warnings
• cargo test --workspace
• TEST_S3_ENDPOINT=http://127.0.0.1:19000 TEST_S3_ACCESS_KEY=accesskey TEST_S3_SECRET_KEY=secretkey cargo test -p rustfs-cli --features integration test_ls_versions_lists_multiple_object_versions -- --nocapture

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