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/terser/dist/package.json

@@ -0,0 +1,10 @@
+{
+  "name": "dist",
+  "private": true,
+  "version": "1.0.0",
+  "main": "bundle.min.js",
+  "type": "commonjs",
+  "author": "",
+  "license": "BSD-2-Clause",
+  "description": "A package to hold the Terser dist bundle as commonjs while keeping the rest of it ESM. Nothing to see here."
+}