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/_parent.js

@@ -0,0 +1,16 @@
+var baseGet = require('./_baseGet'),
+    baseSlice = require('./_baseSlice');
+
+/**
+ * Gets the parent value at `path` of `object`.
+ *
+ * @private
+ * @param {Object} object The object to query.
+ * @param {Array} path The path to get the parent value of.
+ * @returns {*} Returns the parent value.
+ */
+function parent(object, path) {
+  return path.length < 2 ? object : baseGet(object, baseSlice(path, 0, -1));
+}
+
+module.exports = parent;