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/_arraySampleSize.js

@@ -0,0 +1,17 @@
+var baseClamp = require('./_baseClamp'),
+    copyArray = require('./_copyArray'),
+    shuffleSelf = require('./_shuffleSelf');
+
+/**
+ * A specialized version of `_.sampleSize` for arrays.
+ *
+ * @private
+ * @param {Array} array The array to sample.
+ * @param {number} n The number of elements to sample.
+ * @returns {Array} Returns the random elements.
+ */
+function arraySampleSize(array, n) {
+  return shuffleSelf(copyArray(array), baseClamp(n, 0, array.length));
+}
+
+module.exports = arraySampleSize;