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/_shuffleSelf.js

@@ -0,0 +1,28 @@
+var baseRandom = require('./_baseRandom');
+
+/**
+ * A specialized version of `_.shuffle` which mutates and sets the size of `array`.
+ *
+ * @private
+ * @param {Array} array The array to shuffle.
+ * @param {number} [size=array.length] The size of `array`.
+ * @returns {Array} Returns `array`.
+ */
+function shuffleSelf(array, size) {
+  var index = -1,
+      length = array.length,
+      lastIndex = length - 1;
+
+  size = size === undefined ? length : size;
+  while (++index < size) {
+    var rand = baseRandom(index, lastIndex),
+        value = array[rand];
+
+    array[rand] = array[index];
+    array[index] = value;
+  }
+  array.length = size;
+  return array;
+}
+
+module.exports = shuffleSelf;