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/universalify/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "universalify",
+  "version": "2.0.1",
+  "description": "Make a callback- or promise-based function support both promises and callbacks.",
+  "keywords": [
+    "callback",
+    "native",
+    "promise"
+  ],
+  "homepage": "https://github.com/RyanZim/universalify#readme",
+  "bugs": "https://github.com/RyanZim/universalify/issues",
+  "license": "MIT",
+  "author": "Ryan Zimmerman <opensrc@ryanzim.com>",
+  "files": [
+    "index.js"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/RyanZim/universalify.git"
+  },
+  "scripts": {
+    "test": "standard && nyc --reporter text --reporter lcovonly tape test/*.js | colortape"
+  },
+  "devDependencies": {
+    "colortape": "^0.1.2",
+    "coveralls": "^3.0.1",
+    "nyc": "^15.0.0",
+    "standard": "^14.3.1",
+    "tape": "^5.0.1"
+  },
+  "engines": {
+    "node": ">= 10.0.0"
+  }
+}