v8.0.0

Changed (breaking)

• clean --older-than is replaced by clean --before, which accepts either a
  relative delta (7d, 24h, 30m) or an absolute timestamp (2026-06-05,
  '2026-06-05 14:30', or an RFC3339 datetime). Bare/naive timestamps are read
  in the local timezone. The cutoff is exclusive (created before), so
  --before=2026-06-05 cleans jobs up to but not including the start of that
  local day. Migrate --older-than 7d to --before 7d.