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/concat.js

@@ -0,0 +1,43 @@
+var arrayPush = require('./_arrayPush'),
+    baseFlatten = require('./_baseFlatten'),
+    copyArray = require('./_copyArray'),
+    isArray = require('./isArray');
+
+/**
+ * Creates a new array concatenating `array` with any additional arrays
+ * and/or values.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Array
+ * @param {Array} array The array to concatenate.
+ * @param {...*} [values] The values to concatenate.
+ * @returns {Array} Returns the new concatenated array.
+ * @example
+ *
+ * var array = [1];
+ * var other = _.concat(array, 2, [3], [[4]]);
+ *
+ * console.log(other);
+ * // => [1, 2, 3, [4]]
+ *
+ * console.log(array);
+ * // => [1]
+ */
+function concat() {
+  var length = arguments.length;
+  if (!length) {
+    return [];
+  }
+  var args = Array(length - 1),
+      array = arguments[0],
+      index = length;
+
+  while (index--) {
+    args[index - 1] = arguments[index];
+  }
+  return arrayPush(isArray(array) ? copyArray(array) : [array], baseFlatten(args, 1));
+}
+
+module.exports = concat;