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/fast-deep-equal/package.json

@@ -0,0 +1,61 @@
+{
+  "name": "fast-deep-equal",
+  "version": "3.1.3",
+  "description": "Fast deep equal",
+  "main": "index.js",
+  "scripts": {
+    "eslint": "eslint *.js benchmark/*.js spec/*.js",
+    "build": "node build",
+    "benchmark": "npm i && npm run build && cd ./benchmark && npm i && node ./",
+    "test-spec": "mocha spec/*.spec.js -R spec",
+    "test-cov": "nyc npm run test-spec",
+    "test-ts": "tsc --target ES5 --noImplicitAny index.d.ts",
+    "test": "npm run build && npm run eslint && npm run test-ts && npm run test-cov",
+    "prepublish": "npm run build"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/epoberezkin/fast-deep-equal.git"
+  },
+  "keywords": [
+    "fast",
+    "equal",
+    "deep-equal"
+  ],
+  "author": "Evgeny Poberezkin",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/epoberezkin/fast-deep-equal/issues"
+  },
+  "homepage": "https://github.com/epoberezkin/fast-deep-equal#readme",
+  "devDependencies": {
+    "coveralls": "^3.1.0",
+    "dot": "^1.1.2",
+    "eslint": "^7.2.0",
+    "mocha": "^7.2.0",
+    "nyc": "^15.1.0",
+    "pre-commit": "^1.2.2",
+    "react": "^16.12.0",
+    "react-test-renderer": "^16.12.0",
+    "sinon": "^9.0.2",
+    "typescript": "^3.9.5"
+  },
+  "nyc": {
+    "exclude": [
+      "**/spec/**",
+      "node_modules"
+    ],
+    "reporter": [
+      "lcov",
+      "text-summary"
+    ]
+  },
+  "files": [
+    "index.js",
+    "index.d.ts",
+    "react.js",
+    "react.d.ts",
+    "es6/"
+  ],
+  "types": "index.d.ts"
+}