New device-local setting "Monatsansicht seitenweise wischen" (@AppStorage, no
server sync). Off keeps the continuous vertical scroll feed; on switches the
month view to a paged TabView — one month per screen, six height-filling week
rows, swipe left/right to change month (bounded ±monthsBack/Ahead range to keep
the TabView light). WeekRow gains a fillHeight flag so the same row renders at a
fixed height (scroll) or fills the page evenly (paged); its inner cells/divider
now size to the actual geometry. Paged selection is two-way bound to the store's
current date so prev/next/today and the title stay in sync.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>