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-build/build/get-manifest.d.ts

@@ -0,0 +1,20 @@
+import { GetManifestOptions, GetManifestResult } from './types';
+/**
+ * This method returns a list of URLs to precache, referred to as a "precache
+ * manifest", along with details about the number of entries and their size,
+ * based on the options you provide.
+ *
+ * ```
+ * // The following lists some common options; see the rest of the documentation
+ * // for the full set of options and defaults.
+ * const {count, manifestEntries, size, warnings} = await getManifest({
+ *   dontCacheBustURLsMatching: [new RegExp('...')],
+ *   globDirectory: '...',
+ *   globPatterns: ['...', '...'],
+ *   maximumFileSizeToCacheInBytes: ...,
+ * });
+ * ```
+ *
+ * @memberof workbox-build
+ */
+export declare function getManifest(config: GetManifestOptions): Promise<GetManifestResult>;