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/_assignValue.js

@@ -0,0 +1,28 @@
+var baseAssignValue = require('./_baseAssignValue'),
+    eq = require('./eq');
+
+/** Used for built-in method references. */
+var objectProto = Object.prototype;
+
+/** Used to check objects for own properties. */
+var hasOwnProperty = objectProto.hasOwnProperty;
+
+/**
+ * Assigns `value` to `key` of `object` if the existing value is not equivalent
+ * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+ * for equality comparisons.
+ *
+ * @private
+ * @param {Object} object The object to modify.
+ * @param {string} key The key of the property to assign.
+ * @param {*} value The value to assign.
+ */
+function assignValue(object, key, value) {
+  var objValue = object[key];
+  if (!(hasOwnProperty.call(object, key) && eq(objValue, value)) ||
+      (value === undefined && !(key in object))) {
+    baseAssignValue(object, key, value);
+  }
+}
+
+module.exports = assignValue;