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/isFunction.js

@@ -0,0 +1,37 @@
+var baseGetTag = require('./_baseGetTag'),
+    isObject = require('./isObject');
+
+/** `Object#toString` result references. */
+var asyncTag = '[object AsyncFunction]',
+    funcTag = '[object Function]',
+    genTag = '[object GeneratorFunction]',
+    proxyTag = '[object Proxy]';
+
+/**
+ * Checks if `value` is classified as a `Function` object.
+ *
+ * @static
+ * @memberOf _
+ * @since 0.1.0
+ * @category Lang
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a function, else `false`.
+ * @example
+ *
+ * _.isFunction(_);
+ * // => true
+ *
+ * _.isFunction(/abc/);
+ * // => false
+ */
+function isFunction(value) {
+  if (!isObject(value)) {
+    return false;
+  }
+  // The use of `Object#toString` avoids issues with the `typeof` operator
+  // in Safari 9 which returns 'object' for typed arrays and other constructors.
+  var tag = baseGetTag(value);
+  return tag == funcTag || tag == genTag || tag == asyncTag || tag == proxyTag;
+}
+
+module.exports = isFunction;