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/require-from-string/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "require-from-string",
+  "version": "2.0.2",
+  "description": "Require module from string",
+  "license": "MIT",
+  "repository": "floatdrop/require-from-string",
+  "author": {
+    "name": "Vsevolod Strukchinsky",
+    "email": "floatdrop@gmail.com",
+    "url": "github.com/floatdrop"
+  },
+  "engines": {
+    "node": ">=0.10.0"
+  },
+  "scripts": {
+    "test": "mocha"
+  },
+  "files": [
+    "index.js"
+  ],
+  "keywords": [
+    ""
+  ],
+  "dependencies": {},
+  "devDependencies": {
+    "mocha": "*"
+  }
+}