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/is-obj/package.json

@@ -0,0 +1,33 @@
+{
+  "name": "is-obj",
+  "version": "1.0.1",
+  "description": "Check if a value is an object",
+  "license": "MIT",
+  "repository": "sindresorhus/is-obj",
+  "author": {
+    "name": "Sindre Sorhus",
+    "email": "sindresorhus@gmail.com",
+    "url": "sindresorhus.com"
+  },
+  "engines": {
+    "node": ">=0.10.0"
+  },
+  "scripts": {
+    "test": "xo && ava"
+  },
+  "files": [
+    "index.js"
+  ],
+  "keywords": [
+    "obj",
+    "object",
+    "is",
+    "check",
+    "test",
+    "type"
+  ],
+  "devDependencies": {
+    "ava": "*",
+    "xo": "*"
+  }
+}