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/lib/module-registry.d.ts

@@ -0,0 +1,33 @@
+/**
+ * Class for keeping track of which Workbox modules are used by the generated
+ * service worker script.
+ *
+ * @private
+ */
+export declare class ModuleRegistry {
+    private readonly _modulesUsed;
+    /**
+     * @private
+     */
+    constructor();
+    /**
+     * @return {Array<string>} A list of all of the import statements that are
+     * needed for the modules being used.
+     * @private
+     */
+    getImportStatements(): Array<string>;
+    /**
+     * @param {string} pkg The workbox package that the module belongs to.
+     * @param {string} moduleName The name of the module to import.
+     * @return {string} The local variable name that corresponds to that module.
+     * @private
+     */
+    getLocalName(pkg: string, moduleName: string): string;
+    /**
+     * @param {string} pkg The workbox package that the module belongs to.
+     * @param {string} moduleName The name of the module to import.
+     * @return {string} The local variable name that corresponds to that module.
+     * @private
+     */
+    use(pkg: string, moduleName: string): string;
+}