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/_strictIndexOf.js

@@ -0,0 +1,23 @@
+/**
+ * A specialized version of `_.indexOf` which performs strict equality
+ * comparisons of values, i.e. `===`.
+ *
+ * @private
+ * @param {Array} array The array to inspect.
+ * @param {*} value The value to search for.
+ * @param {number} fromIndex The index to search from.
+ * @returns {number} Returns the index of the matched value, else `-1`.
+ */
+function strictIndexOf(array, value, fromIndex) {
+  var index = fromIndex - 1,
+      length = array.length;
+
+  while (++index < length) {
+    if (array[index] === value) {
+      return index;
+    }
+  }
+  return -1;
+}
+
+module.exports = strictIndexOf;