feat(ecstore): add RUSTFS_ILM_DEBUG_DAY_SECS lifecycle time-acceleration for tests (backlog#1148 ilm-5)
Model a Ceph rgw_lc_debug_interval-style switch: when RUSTFS_ILM_DEBUG_DAY_SECS
is set to a positive integer N, lifecycle Days-based rule evaluation treats one
'day' as N seconds instead of 86400, so Days>=1 expiration/transition/noncurrent
rules become exercisable in seconds. Unset => byte-identical to production.
All Days->deadline conversions funnel through expected_expiry_time(); the new
ilm_day_secs() helper (OnceLock-cached in production, env-read under cfg(test))
rescales both the day offset and the default rounding boundary. An explicit
RUSTFS_ILM_PROCESS_TIME still wins for the rounding boundary. Absolute Date-based
rules are deliberately NOT rescaled. Activation emits a WARN; test/debug only.
Refs rustfs/backlog#1148 (ilm-5), rustfs/backlog#1155.
Zhengchao An