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/vitest/dist/chunks/mocker.cRtM890J.d.ts

@@ -0,0 +1,17 @@
+import { MockedModuleType } from '@vitest/mocker';
+
+type Promisable<T> = T | Promise<T>;
+type MockFactoryWithHelper<M = unknown> = (importOriginal: <T extends M = M>() => Promise<T>) => Promisable<Partial<M>>;
+type MockFactory = () => any;
+interface MockOptions {
+    spy?: boolean;
+}
+interface PendingSuiteMock {
+    id: string;
+    importer: string;
+    action: 'mock' | 'unmock';
+    type?: MockedModuleType;
+    factory?: MockFactory;
+}
+
+export type { MockFactoryWithHelper as M, PendingSuiteMock as P, MockOptions as a, MockFactory as b };