Add monoline icons to the topbar coordinates/sun readout

WAYPOINT_ICON (coords) and PENDING_ICON (countdown) reused as-is; two new
hand-drawn SUNRISE_ICON/SUNSET_ICON since NPS's symbol set has no match —
same currentColor stroke style as the rest of icons.js, so they render
monochrome in the dark topbar rather than colored emoji.

sun.js's formatSunInfo now returns {sunrise, sunset, countdown} instead of
one joined string, so map.js can place its own icon in front of each
piece instead of the module owning any markup.

public/js/sun.js

@@ -45,7 +45,9 @@ const DAY_MS = 24 * 60 * 60 * 1000;
 // null when there's no sunrise/sunset to show at all — getTimes returns
 // null (not Invalid Date) for both on a polar day/night, per its own
 // comment in suncalc.js — the caller just hides the readout in that case
-// rather than showing something misleading.
+// rather than showing something misleading. Returns the three pieces
+// separately (not one joined string) so the caller can put its own icon in
+// front of each rather than this module owning any markup.
 export function formatSunInfo(lat, lng, now = new Date()) {
   const today = getTimes(now, lat, lng);
   if (today.sunrise === null || today.sunset === null) return null;
@@ -61,6 +63,9 @@ export function formatSunInfo(lat, lng, now = new Date()) {
     next = tomorrow.sunrise === null ? null : { label: "sunrise", at: tomorrow.sunrise };
   }
 
-  const countdown = next ? ` · ${formatCountdown(next.at - now)} to ${next.label}` : "";
-  return `${formatTime(today.sunrise)}–${formatTime(today.sunset)}${countdown}`;
+  return {
+    sunrise: formatTime(today.sunrise),
+    sunset: formatTime(today.sunset),
+    countdown: next ? `${formatCountdown(next.at - now)} to ${next.label}` : null,
+  };
 }