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/negate.js

@@ -0,0 +1,40 @@
+/** Error message constants. */
+var FUNC_ERROR_TEXT = 'Expected a function';
+
+/**
+ * Creates a function that negates the result of the predicate `func`. The
+ * `func` predicate is invoked with the `this` binding and arguments of the
+ * created function.
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category Function
+ * @param {Function} predicate The predicate to negate.
+ * @returns {Function} Returns the new negated function.
+ * @example
+ *
+ * function isEven(n) {
+ *   return n % 2 == 0;
+ * }
+ *
+ * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
+ * // => [1, 3, 5]
+ */
+function negate(predicate) {
+  if (typeof predicate != 'function') {
+    throw new TypeError(FUNC_ERROR_TEXT);
+  }
+  return function() {
+    var args = arguments;
+    switch (args.length) {
+      case 0: return !predicate.call(this);
+      case 1: return !predicate.call(this, args[0]);
+      case 2: return !predicate.call(this, args[0], args[1]);
+      case 3: return !predicate.call(this, args[0], args[1], args[2]);
+    }
+    return !predicate.apply(this, args);
+  };
+}
+
+module.exports = negate;