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/update-browserslist-db/package.json

@@ -0,0 +1,40 @@
+{
+  "name": "update-browserslist-db",
+  "version": "1.2.3",
+  "description": "CLI tool to update caniuse-lite to refresh target browsers from Browserslist config",
+  "keywords": [
+    "caniuse",
+    "browsers",
+    "target"
+  ],
+  "funding": [
+    {
+      "type": "opencollective",
+      "url": "https://opencollective.com/browserslist"
+    },
+    {
+      "type": "tidelift",
+      "url": "https://tidelift.com/funding/github/npm/browserslist"
+    },
+    {
+      "type": "github",
+      "url": "https://github.com/sponsors/ai"
+    }
+  ],
+  "author": "Andrey Sitnik <andrey@sitnik.ru>",
+  "license": "MIT",
+  "repository": "browserslist/update-db",
+  "types": "./index.d.ts",
+  "exports": {
+    ".": "./index.js",
+    "./package.json": "./package.json"
+  },
+  "dependencies": {
+    "escalade": "^3.2.0",
+    "picocolors": "^1.1.1"
+  },
+  "peerDependencies": {
+    "browserslist": ">= 4.21.0"
+  },
+  "bin": "cli.js"
+}