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/_basePickBy.js

@@ -0,0 +1,30 @@
+var baseGet = require('./_baseGet'),
+    baseSet = require('./_baseSet'),
+    castPath = require('./_castPath');
+
+/**
+ * The base implementation of  `_.pickBy` without support for iteratee shorthands.
+ *
+ * @private
+ * @param {Object} object The source object.
+ * @param {string[]} paths The property paths to pick.
+ * @param {Function} predicate The function invoked per property.
+ * @returns {Object} Returns the new object.
+ */
+function basePickBy(object, paths, predicate) {
+  var index = -1,
+      length = paths.length,
+      result = {};
+
+  while (++index < length) {
+    var path = paths[index],
+        value = baseGet(object, path);
+
+    if (predicate(value, path)) {
+      baseSet(result, castPath(path, object), value);
+    }
+  }
+  return result;
+}
+
+module.exports = basePickBy;