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/set-function-length/env.js

@@ -0,0 +1,25 @@
+'use strict';
+
+var gOPD = require('gopd');
+var bind = require('function-bind');
+
+var unbound = gOPD && gOPD(function () {}, 'length');
+// @ts-expect-error ts(2555) TS is overly strict with .call
+var bound = gOPD && gOPD(bind.call(function () {}), 'length');
+
+var functionsHaveConfigurableLengths = !!(unbound && unbound.configurable);
+
+var functionsHaveWritableLengths = !!(unbound && unbound.writable);
+
+var boundFnsHaveConfigurableLengths = !!(bound && bound.configurable);
+
+var boundFnsHaveWritableLengths = !!(bound && bound.writable);
+
+/** @type {import('./env')} */
+module.exports = {
+	__proto__: null,
+	boundFnsHaveConfigurableLengths: boundFnsHaveConfigurableLengths,
+	boundFnsHaveWritableLengths: boundFnsHaveWritableLengths,
+	functionsHaveConfigurableLengths: functionsHaveConfigurableLengths,
+	functionsHaveWritableLengths: functionsHaveWritableLengths
+};