fix(contracts): reject invalid legacy intervals

Keep positive sub-minute schedules readable without accepting corrupt zero or negative persisted intervals.

Co-authored-by: codex <codex@users.noreply.github.com>
387d17049dJulius Marminge committed on 8/29/2026, 6:01:51 AMparentc0b1e7a
2 files changedLine totals unavailable