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-precaching/precacheAndRoute.d.ts

@@ -0,0 +1,18 @@
+import { PrecacheRouteOptions, PrecacheEntry } from './_types.js';
+import './_version.js';
+/**
+ * This method will add entries to the precache list and add a route to
+ * respond to fetch events.
+ *
+ * This is a convenience method that will call
+ * {@link workbox-precaching.precache} and
+ * {@link workbox-precaching.addRoute} in a single call.
+ *
+ * @param {Array<Object|string>} entries Array of entries to precache.
+ * @param {Object} [options] See the
+ * {@link workbox-precaching.PrecacheRoute} options.
+ *
+ * @memberof workbox-precaching
+ */
+declare function precacheAndRoute(entries: Array<PrecacheEntry | string>, options?: PrecacheRouteOptions): void;
+export { precacheAndRoute };