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/_baseExtremum.js

@@ -0,0 +1,32 @@
+var isSymbol = require('./isSymbol');
+
+/**
+ * The base implementation of methods like `_.max` and `_.min` which accepts a
+ * `comparator` to determine the extremum value.
+ *
+ * @private
+ * @param {Array} array The array to iterate over.
+ * @param {Function} iteratee The iteratee invoked per iteration.
+ * @param {Function} comparator The comparator used to compare values.
+ * @returns {*} Returns the extremum value.
+ */
+function baseExtremum(array, iteratee, comparator) {
+  var index = -1,
+      length = array.length;
+
+  while (++index < length) {
+    var value = array[index],
+        current = iteratee(value);
+
+    if (current != null && (computed === undefined
+          ? (current === current && !isSymbol(current))
+          : comparator(current, computed)
+        )) {
+      var computed = current,
+          result = value;
+    }
+  }
+  return result;
+}
+
+module.exports = baseExtremum;