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/@vitest/utils/package.json

@@ -0,0 +1,77 @@
+{
+  "name": "@vitest/utils",
+  "type": "module",
+  "version": "2.1.9",
+  "description": "Shared Vitest utility functions",
+  "license": "MIT",
+  "funding": "https://opencollective.com/vitest",
+  "homepage": "https://github.com/vitest-dev/vitest/tree/main/packages/utils#readme",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/vitest-dev/vitest.git",
+    "directory": "packages/utils"
+  },
+  "bugs": {
+    "url": "https://github.com/vitest-dev/vitest/issues"
+  },
+  "sideEffects": false,
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    },
+    "./diff": {
+      "types": "./dist/diff.d.ts",
+      "default": "./dist/diff.js"
+    },
+    "./ast": {
+      "types": "./dist/ast.d.ts",
+      "default": "./dist/ast.js"
+    },
+    "./error": {
+      "types": "./dist/error.d.ts",
+      "default": "./dist/error.js"
+    },
+    "./helpers": {
+      "types": "./dist/helpers.d.ts",
+      "default": "./dist/helpers.js"
+    },
+    "./source-map": {
+      "types": "./dist/source-map.d.ts",
+      "default": "./dist/source-map.js"
+    },
+    "./*": "./*"
+  },
+  "main": "./dist/index.js",
+  "module": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "typesVersions": {
+    "*": {
+      "ast": [
+        "dist/ast.d.ts"
+      ],
+      "source-map": [
+        "dist/source-map.d.ts"
+      ]
+    }
+  },
+  "files": [
+    "*.d.ts",
+    "dist"
+  ],
+  "dependencies": {
+    "loupe": "^3.1.2",
+    "tinyrainbow": "^1.2.0",
+    "@vitest/pretty-format": "2.1.9"
+  },
+  "devDependencies": {
+    "@jridgewell/trace-mapping": "^0.3.25",
+    "@types/estree": "^1.0.6",
+    "diff-sequences": "^29.6.3",
+    "tinyhighlight": "^0.3.2"
+  },
+  "scripts": {
+    "build": "rimraf dist && rollup -c",
+    "dev": "rollup -c --watch"
+  }
+}