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/unset.js

@@ -0,0 +1,34 @@
+var baseUnset = require('./_baseUnset');
+
+/**
+ * Removes the property at `path` of `object`.
+ *
+ * **Note:** This method mutates `object`.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Object
+ * @param {Object} object The object to modify.
+ * @param {Array|string} path The path of the property to unset.
+ * @returns {boolean} Returns `true` if the property is deleted, else `false`.
+ * @example
+ *
+ * var object = { 'a': [{ 'b': { 'c': 7 } }] };
+ * _.unset(object, 'a[0].b.c');
+ * // => true
+ *
+ * console.log(object);
+ * // => { 'a': [{ 'b': {} }] };
+ *
+ * _.unset(object, ['a', '0', 'b', 'c']);
+ * // => true
+ *
+ * console.log(object);
+ * // => { 'a': [{ 'b': {} }] };
+ */
+function unset(object, path) {
+  return object == null ? true : baseUnset(object, path);
+}
+
+module.exports = unset;