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/caniuse-lite/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "caniuse-lite",
+  "version": "1.0.30001777",
+  "description": "A smaller version of caniuse-db, with only the essentials!",
+  "main": "dist/unpacker/index.js",
+  "files": [
+    "data",
+    "dist"
+  ],
+  "keywords": [
+    "support"
+  ],
+  "author": {
+    "name": "Ben Briggs",
+    "email": "beneb.info@gmail.com",
+    "url": "http://beneb.info"
+  },
+  "repository": "browserslist/caniuse-lite",
+  "funding": [
+    {
+      "type": "opencollective",
+      "url": "https://opencollective.com/browserslist"
+    },
+    {
+      "type": "tidelift",
+      "url": "https://tidelift.com/funding/github/npm/caniuse-lite"
+    },
+    {
+      "type": "github",
+      "url": "https://github.com/sponsors/ai"
+    }
+  ],
+  "license": "CC-BY-4.0"
+}