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/lodash.sortby/package.json

@@ -0,0 +1,17 @@
+{
+  "name": "lodash.sortby",
+  "version": "4.7.0",
+  "description": "The lodash method `_.sortBy` exported as a module.",
+  "homepage": "https://lodash.com/",
+  "icon": "https://lodash.com/icon.svg",
+  "license": "MIT",
+  "keywords": "lodash-modularized, sortby",
+  "author": "John-David Dalton <john.david.dalton@gmail.com> (http://allyoucanleet.com/)",
+  "contributors": [
+    "John-David Dalton <john.david.dalton@gmail.com> (http://allyoucanleet.com/)",
+    "Blaine Bublitz <blaine.bublitz@gmail.com> (https://github.com/phated)",
+    "Mathias Bynens <mathias@qiwi.be> (https://mathiasbynens.be/)"
+  ],
+  "repository": "lodash/lodash",
+  "scripts": { "test": "echo \"See https://travis-ci.org/lodash/lodash-cli for testing details.\"" }
+}