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/tsx/dist/esm/api/index.d.cts

@@ -0,0 +1,35 @@
+import { MessagePort } from 'node:worker_threads';
+import { R as RequiredProperty } from '../../types-Cxp8y2TL.js';
+
+type ScopedImport = (specifier: string, parent: string) => Promise<any>;
+
+type TsconfigOptions = false | string;
+type InitializationOptions = {
+    namespace?: string;
+    port?: MessagePort;
+    tsconfig?: TsconfigOptions;
+};
+type RegisterOptions = {
+    namespace?: string;
+    onImport?: (url: string) => void;
+    tsconfig?: TsconfigOptions;
+};
+type Unregister = () => Promise<void>;
+type NamespacedUnregister = Unregister & {
+    import: ScopedImport;
+    unregister: Unregister;
+};
+type Register = {
+    (options: RequiredProperty<RegisterOptions, 'namespace'>): NamespacedUnregister;
+    (options?: RegisterOptions): Unregister;
+};
+declare const register: Register;
+
+type Options = {
+    parentURL: string;
+    onImport?: (url: string) => void;
+    tsconfig?: TsconfigOptions;
+};
+declare const tsImport: (specifier: string, options: string | Options) => Promise<any>;
+
+export { type InitializationOptions, type NamespacedUnregister, type Register, type RegisterOptions, type ScopedImport, type Unregister, register, tsImport };