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/slice.js

@@ -0,0 +1,37 @@
+var baseSlice = require('./_baseSlice'),
+    isIterateeCall = require('./_isIterateeCall'),
+    toInteger = require('./toInteger');
+
+/**
+ * Creates a slice of `array` from `start` up to, but not including, `end`.
+ *
+ * **Note:** This method is used instead of
+ * [`Array#slice`](https://mdn.io/Array/slice) to ensure dense arrays are
+ * returned.
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category Array
+ * @param {Array} array The array to slice.
+ * @param {number} [start=0] The start position.
+ * @param {number} [end=array.length] The end position.
+ * @returns {Array} Returns the slice of `array`.
+ */
+function slice(array, start, end) {
+  var length = array == null ? 0 : array.length;
+  if (!length) {
+    return [];
+  }
+  if (end && typeof end != 'number' && isIterateeCall(array, start, end)) {
+    start = 0;
+    end = length;
+  }
+  else {
+    start = start == null ? 0 : toInteger(start);
+    end = end === undefined ? length : toInteger(end);
+  }
+  return baseSlice(array, start, end);
+}
+
+module.exports = slice;