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/last.js

@@ -0,0 +1,20 @@
+/**
+ * Gets the last element of `array`.
+ *
+ * @static
+ * @memberOf _
+ * @since 0.1.0
+ * @category Array
+ * @param {Array} array The array to query.
+ * @returns {*} Returns the last element of `array`.
+ * @example
+ *
+ * _.last([1, 2, 3]);
+ * // => 3
+ */
+function last(array) {
+  var length = array == null ? 0 : array.length;
+  return length ? array[length - 1] : undefined;
+}
+
+module.exports = last;