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/_copyObject.js

@@ -0,0 +1,40 @@
+var assignValue = require('./_assignValue'),
+    baseAssignValue = require('./_baseAssignValue');
+
+/**
+ * Copies properties of `source` to `object`.
+ *
+ * @private
+ * @param {Object} source The object to copy properties from.
+ * @param {Array} props The property identifiers to copy.
+ * @param {Object} [object={}] The object to copy properties to.
+ * @param {Function} [customizer] The function to customize copied values.
+ * @returns {Object} Returns `object`.
+ */
+function copyObject(source, props, object, customizer) {
+  var isNew = !object;
+  object || (object = {});
+
+  var index = -1,
+      length = props.length;
+
+  while (++index < length) {
+    var key = props[index];
+
+    var newValue = customizer
+      ? customizer(object[key], source[key], key, object, source)
+      : undefined;
+
+    if (newValue === undefined) {
+      newValue = source[key];
+    }
+    if (isNew) {
+      baseAssignValue(object, key, newValue);
+    } else {
+      assignValue(object, key, newValue);
+    }
+  }
+  return object;
+}
+
+module.exports = copyObject;