Add progressive web app companion for cross-platform access

Vite + TypeScript PWA that mirrors the Android app's core features:
- Pre-processed shelter data (build-time UTM33N→WGS84 conversion)
- Leaflet map with shelter markers, user location, and offline tiles
- Canvas compass arrow (ported from DirectionArrowView.kt)
- IndexedDB shelter cache with 7-day staleness check
- Service worker with CacheFirst tiles and precached app shell
- i18n for en, nb, nn (ported from Android strings.xml)
- iOS/Android compass handling with low-pass filter
- Respects user map interaction (no auto-snap on pan/zoom)
- Build revision cache-breaker for reliable SW updates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pwa/node_modules/lodash/now.js

@@ -0,0 +1,23 @@
+var root = require('./_root');
+
+/**
+ * Gets the timestamp of the number of milliseconds that have elapsed since
+ * the Unix epoch (1 January 1970 00:00:00 UTC).
+ *
+ * @static
+ * @memberOf _
+ * @since 2.4.0
+ * @category Date
+ * @returns {number} Returns the timestamp.
+ * @example
+ *
+ * _.defer(function(stamp) {
+ *   console.log(_.now() - stamp);
+ * }, _.now());
+ * // => Logs the number of milliseconds it took for the deferred invocation.
+ */
+var now = function() {
+  return root.Date.now();
+};
+
+module.exports = now;