test(admin): cover ILM wait timeout

[overtrue]

Summary

• Add a focused CLI regression test for admin ilm transition wait timing out before the backend reports a terminal job state.
• Assert the timeout keeps the v3 JSON error on stderr, returns the general error exit code, and polls the durable job endpoint twice.

Evidence

• Recent ILM transition job work added success-path wait coverage, but the timeout branch was not exercised.

Validation

• RUSTC_WRAPPER= cargo test -p rustfs-cli --test admin_ilm ilm_transition_wait_times_out_before_terminal_state -- --nocapture
• RUSTC_WRAPPER= CARGO_BUILD_JOBS=2 make pre-commit

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