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/es-abstract/index.js

@@ -0,0 +1,38 @@
+'use strict';
+
+var assign = require('./helpers/assign');
+
+var ES5 = require('./es5');
+var ES2015 = require('./es2015');
+var ES2016 = require('./es2016');
+var ES2017 = require('./es2017');
+var ES2018 = require('./es2018');
+var ES2019 = require('./es2019');
+var ES2020 = require('./es2020');
+var ES2021 = require('./es2021');
+var ES2022 = require('./es2022');
+var ES2023 = require('./es2023');
+var ES2024 = require('./es2024');
+var ES2025 = require('./es2025');
+
+var ES = {
+	ES5: ES5,
+	ES6: ES2015,
+	ES2015: ES2015,
+	ES7: ES2016,
+	ES2016: ES2016,
+	ES2017: ES2017,
+	ES2018: ES2018,
+	ES2019: ES2019,
+	ES2020: ES2020,
+	ES2021: ES2021,
+	ES2022: ES2022,
+	ES2023: ES2023,
+	ES2024: ES2024,
+	ES2025: ES2025
+};
+assign(ES, ES5);
+delete ES.CheckObjectCoercible; // renamed in ES6 to RequireObjectCoercible
+assign(ES, ES2015);
+
+module.exports = ES;