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/assertion-error/package.json

@@ -0,0 +1,32 @@
+{
+  "name": "assertion-error",
+  "version": "2.0.1",
+  "description": "Error constructor for test and validation frameworks that implements standardized AssertionError specification.",
+  "author": "Jake Luer <jake@qualiancy.com> (http://qualiancy.com)",
+  "license": "MIT",
+  "types": "./index.d.ts",
+  "keywords": [
+    "test",
+    "assertion",
+    "assertion-error"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git@github.com:chaijs/assertion-error.git"
+  },
+  "engines": {
+    "node": ">=12"
+  },
+  "files": [
+    "index.d.ts"
+  ],
+  "type": "module",
+  "module": "index.js",
+  "main": "index.js",
+  "scripts": {
+    "build": "deno bundle mod.ts > index.js",
+    "pretest": "rm -rf coverage/",
+    "test": "deno test --coverage=coverage",
+    "posttest": "deno coverage coverage --lcov > coverage/lcov.info && lcov --summary coverage/lcov.info"
+  }
+}