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/_baseReduce.js

@@ -0,0 +1,23 @@
+/**
+ * The base implementation of `_.reduce` and `_.reduceRight`, without support
+ * for iteratee shorthands, which iterates over `collection` using `eachFunc`.
+ *
+ * @private
+ * @param {Array|Object} collection The collection to iterate over.
+ * @param {Function} iteratee The function invoked per iteration.
+ * @param {*} accumulator The initial value.
+ * @param {boolean} initAccum Specify using the first or last element of
+ *  `collection` as the initial value.
+ * @param {Function} eachFunc The function to iterate over `collection`.
+ * @returns {*} Returns the accumulated value.
+ */
+function baseReduce(collection, iteratee, accumulator, initAccum, eachFunc) {
+  eachFunc(collection, function(value, index, collection) {
+    accumulator = initAccum
+      ? (initAccum = false, value)
+      : iteratee(accumulator, value, index, collection);
+  });
+  return accumulator;
+}
+
+module.exports = baseReduce;