.default(null) rather than a bare .nullable(), and the distinction is the
whole commit: a record written before this field existed has no `repeat`
key, a bare .nullable() rejects a missing key, and useCustom reads through
validRecords — which drops what fails and persists only the survivors. The
stricter form would have erased every reader's custom events on first
launch with no server-side copy.
Also refuses a window that comes round before it closes, since two live
occurrences of one rule leave "what ends soonest" without an answer. Only
when an end is stated; with none the window runs to the next opening and
cannot overlap.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
