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/thru.js

@@ -0,0 +1,28 @@
+/**
+ * This method is like `_.tap` except that it returns the result of `interceptor`.
+ * The purpose of this method is to "pass thru" values replacing intermediate
+ * results in a method chain sequence.
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category Seq
+ * @param {*} value The value to provide to `interceptor`.
+ * @param {Function} interceptor The function to invoke.
+ * @returns {*} Returns the result of `interceptor`.
+ * @example
+ *
+ * _('  abc  ')
+ *  .chain()
+ *  .trim()
+ *  .thru(function(value) {
+ *    return [value];
+ *  })
+ *  .value();
+ * // => ['abc']
+ */
+function thru(value, interceptor) {
+  return interceptor(value);
+}
+
+module.exports = thru;