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/index.js

@@ -0,0 +1,19 @@
+export { c as createExpect, a as expect, v as vi, b as vitest } from './chunks/vi.DgezovHB.js';
+export { b as assertType, g as getRunningMode, i as inject, a as isWatchMode } from './chunks/index.ckWaX2gY.js';
+export { i as isFirstRun, a as runOnce } from './chunks/run-once.2ogXb3JV.js';
+export { b as bench } from './chunks/benchmark.Cdu9hjj4.js';
+export { expectTypeOf } from 'expect-type';
+export { afterAll, afterEach, beforeAll, beforeEach, describe, it, onTestFailed, onTestFinished, suite, test } from '@vitest/runner';
+import * as chai from 'chai';
+export { chai };
+export { assert, should } from 'chai';
+import '@vitest/expect';
+import '@vitest/runner/utils';
+import './chunks/utils.C8RiOc4B.js';
+import '@vitest/utils';
+import './chunks/_commonjsHelpers.BFTU3MAI.js';
+import '@vitest/snapshot';
+import '@vitest/utils/error';
+import '@vitest/utils/source-map';
+import './chunks/date.W2xKR2qe.js';
+import '@vitest/spy';