Previously only the small day-number was a tap target, so tapping the
blank area of a day cell (or its "+N" overflow) did nothing. Make every
non-event part of a day column open that day — the day number, the empty
lane cells, and the overflow row — via a shared openDayAction, so a tap
anywhere on a day opens it, matching the in-app month grid. Event bars
keep opting out to open their own detail.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>