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/clone.js

@@ -0,0 +1,36 @@
+var baseClone = require('./_baseClone');
+
+/** Used to compose bitmasks for cloning. */
+var CLONE_SYMBOLS_FLAG = 4;
+
+/**
+ * Creates a shallow clone of `value`.
+ *
+ * **Note:** This method is loosely based on the
+ * [structured clone algorithm](https://mdn.io/Structured_clone_algorithm)
+ * and supports cloning arrays, array buffers, booleans, date objects, maps,
+ * numbers, `Object` objects, regexes, sets, strings, symbols, and typed
+ * arrays. The own enumerable properties of `arguments` objects are cloned
+ * as plain objects. An empty object is returned for uncloneable values such
+ * as error objects, functions, DOM nodes, and WeakMaps.
+ *
+ * @static
+ * @memberOf _
+ * @since 0.1.0
+ * @category Lang
+ * @param {*} value The value to clone.
+ * @returns {*} Returns the cloned value.
+ * @see _.cloneDeep
+ * @example
+ *
+ * var objects = [{ 'a': 1 }, { 'b': 2 }];
+ *
+ * var shallow = _.clone(objects);
+ * console.log(shallow[0] === objects[0]);
+ * // => true
+ */
+function clone(value) {
+  return baseClone(value, CLONE_SYMBOLS_FLAG);
+}
+
+module.exports = clone;