test(admin): cover real backend ILM job commands

[houseme]

Summary

• Add an ignored real-backend integration test for rc admin ilm transition run --async, status, wait, and cancel.
• Start a local RustFS child process from RC_REAL_RUSTFS_BINARY, configure RC_HOST_realilm, and verify the CLI talks to the real admin backend instead of the fake test server.
• Assert that terminal cancel does not rewrite a finished job into cancelled.

Verification

• cargo fmt --all --check
• cargo clippy -p rustfs-cli --test admin_ilm_real_backend -- -D warnings
• cargo clippy --workspace -- -D warnings
• cargo test -p rustfs-cli --test admin_ilm_real_backend -- --list
• RC_REAL_RUSTFS_BINARY=/private/tmp/rustfs-1479-task-journal-attribution/target/debug/rustfs cargo test -p rustfs-cli --test admin_ilm_real_backend -- --ignored --nocapture
• cargo test --workspace

Notes

• The real-backend test is ignored by default because it requires an external RustFS binary via RC_REAL_RUSTFS_BINARY.