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/workbox-recipes/googleFontsCache.d.ts

@@ -0,0 +1,18 @@
+import './_version.js';
+export interface GoogleFontCacheOptions {
+    cachePrefix?: string;
+    maxAgeSeconds?: number;
+    maxEntries?: number;
+}
+/**
+ * An implementation of the [Google fonts]{@link https://developers.google.com/web/tools/workbox/guides/common-recipes#google_fonts} caching recipe
+ *
+ * @memberof workbox-recipes
+ *
+ * @param {Object} [options]
+ * @param {string} [options.cachePrefix] Cache prefix for caching stylesheets and webfonts. Defaults to google-fonts
+ * @param {number} [options.maxAgeSeconds] Maximum age, in seconds, that font entries will be cached for. Defaults to 1 year
+ * @param {number} [options.maxEntries] Maximum number of fonts that will be cached. Defaults to 30
+ */
+declare function googleFontsCache(options?: GoogleFontCacheOptions): void;
+export { googleFontsCache };