Fix mouse-wheel scrolling in the main app and the dashboard sun arc

- overscroll-behavior moved from <body> to <html>: with html+body both overflow-x:hidden,
  body is a scroll container and the rule blocked wheel scrolling from reaching the page
- sunTimes returned the neighbouring day's sunrise/sunset (julian-day rounding), so midday
  looked like night; align results to the requested local day

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

app/public/dashboard.html

@@ -335,7 +335,8 @@ canvas.sparkline { display: block; width: 100%; height: 22px; margin-top: 0.4rem
 
 /* ── iPhone / touch ── */
 html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; -webkit-tap-highlight-color: transparent; }
-body { overscroll-behavior-y: none; min-height: 100vh; min-height: 100dvh; }
+html { overscroll-behavior-y: none; }
+body { min-height: 100vh; min-height: 100dvh; }
 .header { padding-top: calc(1rem + env(safe-area-inset-top)); padding-left: calc(1.5rem + env(safe-area-inset-left)); padding-right: calc(1.5rem + env(safe-area-inset-right)); }
 .page { padding-left: calc(1rem + env(safe-area-inset-left)); padding-right: calc(1rem + env(safe-area-inset-right)); padding-bottom: calc(4rem + env(safe-area-inset-bottom)); }
 /* Let the page scroll when a finger starts on a chart; taps/long-press still show tooltips */