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/tinyspy/dist/index.d.cts

@@ -0,0 +1,83 @@
+declare const S: unique symbol;
+
+interface GetState {
+    <A extends any[], R>(spy: SpyInternalImpl<A, R>): SpyInternalImplState<A, R>;
+    <A extends any[], R>(spy: SpyInternal<A, R>): SpyInternalState<A, R>;
+}
+declare let spies: Set<SpyImpl<any[], any>>;
+declare let getInternalState: GetState;
+type ReturnError = ['error', any];
+type ReturnOk<R> = ['ok', R];
+type ResultFn<R> = ReturnError | ReturnOk<R>;
+interface SpyInternal<A extends any[] = any[], R = any> {
+    (this: any, ...args: A): R;
+    [S]: SpyInternalState<A, R>;
+}
+interface SpyInternalImpl<A extends any[] = any[], R = any> extends SpyInternal<A, R> {
+    [S]: SpyInternalImplState<A, R>;
+}
+interface SpyInternalState<A extends any[] = any[], R = any> {
+    called: boolean;
+    callCount: number;
+    calls: A[];
+    results: ResultFn<R>[];
+    resolves: R extends PromiseLike<infer V> ? ResultFn<V>[] : never;
+    reset(): void;
+    impl: ((...args: A) => R) | undefined;
+    next: ResultFn<R>[];
+}
+interface SpyInternalImplState<A extends any[] = any[], R = any> extends SpyInternalState<A, R> {
+    getOriginal(): (...args: A) => R;
+    willCall(cb: (...args: A) => R): this;
+    restore(): void;
+}
+interface Spy<A extends any[] = any[], R = any> extends SpyInternalState<A, R> {
+    returns: R[];
+    length: number;
+    nextError(error: any): this;
+    nextResult(result: R): this;
+}
+interface SpyImpl<A extends any[] = any[], R = any> extends Spy<A, R> {
+    getOriginal(): (...args: A) => R;
+    willCall(cb: (...args: A) => R): this;
+    restore(): void;
+}
+declare function createInternalSpy<A extends any[], R>(cb?: ((...args: A) => R) | {
+    new (...args: A): R;
+}): SpyInternal<A, R>;
+
+interface SpyFn<A extends any[] = any[], R = any> extends Spy<A, R> {
+    new (...args: A): R extends void ? any : R;
+    (...args: A): R;
+}
+declare function spy<A extends any[], R>(cb?: ((...args: A) => R) | {
+    new (...args: A): R;
+}): SpyFn<A, R>;
+
+type Procedure = (...args: any[]) => any;
+type Methods<T> = {
+    [K in keyof T]: T[K] extends Procedure ? K : never;
+}[keyof T];
+type Getters<T> = {
+    [K in keyof T]: T[K] extends Procedure ? never : K;
+}[keyof T];
+type Constructors<T> = {
+    [K in keyof T]: T[K] extends new (...args: any[]) => any ? K : never;
+}[keyof T];
+declare function internalSpyOn<T, K extends string & keyof T>(obj: T, methodName: K | {
+    getter: K;
+} | {
+    setter: K;
+}, mock?: Procedure): SpyInternalImpl<any[], any>;
+declare function spyOn<T, S extends Getters<Required<T>>>(obj: T, methodName: {
+    setter: S;
+}, mock?: (arg: T[S]) => void): SpyImpl<[T[S]], void>;
+declare function spyOn<T, G extends Getters<Required<T>>>(obj: T, methodName: {
+    getter: G;
+}, mock?: () => T[G]): SpyImpl<[], T[G]>;
+declare function spyOn<T, M extends Constructors<Required<T>>>(object: T, method: M): Required<T>[M] extends new (...args: infer A) => infer R ? SpyImpl<A, R> : never;
+declare function spyOn<T, M extends Methods<Required<T>>>(obj: T, methodName: M, mock?: T[M]): Required<T>[M] extends (...args: infer A) => infer R ? SpyImpl<A, R> : never;
+
+declare function restoreAll(): void;
+
+export { type Spy, type SpyFn, type SpyImpl, type SpyInternal, type SpyInternalImpl, createInternalSpy, getInternalState, internalSpyOn, restoreAll, spies, spy, spyOn };