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/_matchesStrictComparable.js

@@ -0,0 +1,20 @@
+/**
+ * A specialized version of `matchesProperty` for source values suitable
+ * for strict equality comparisons, i.e. `===`.
+ *
+ * @private
+ * @param {string} key The key of the property to get.
+ * @param {*} srcValue The value to match.
+ * @returns {Function} Returns the new spec function.
+ */
+function matchesStrictComparable(key, srcValue) {
+  return function(object) {
+    if (object == null) {
+      return false;
+    }
+    return object[key] === srcValue &&
+      (srcValue !== undefined || (key in Object(object)));
+  };
+}
+
+module.exports = matchesStrictComparable;