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/fromPairs.js

@@ -0,0 +1,28 @@
+/**
+ * The inverse of `_.toPairs`; this method returns an object composed
+ * from key-value `pairs`.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Array
+ * @param {Array} pairs The key-value pairs.
+ * @returns {Object} Returns the new object.
+ * @example
+ *
+ * _.fromPairs([['a', 1], ['b', 2]]);
+ * // => { 'a': 1, 'b': 2 }
+ */
+function fromPairs(pairs) {
+  var index = -1,
+      length = pairs == null ? 0 : pairs.length,
+      result = {};
+
+  while (++index < length) {
+    var pair = pairs[index];
+    result[pair[0]] = pair[1];
+  }
+  return result;
+}
+
+module.exports = fromPairs;