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/semver/package.json

@@ -0,0 +1,38 @@
+{
+  "name": "semver",
+  "version": "6.3.1",
+  "description": "The semantic version parser used by npm.",
+  "main": "semver.js",
+  "scripts": {
+    "test": "tap test/ --100 --timeout=30",
+    "lint": "echo linting disabled",
+    "postlint": "template-oss-check",
+    "template-oss-apply": "template-oss-apply --force",
+    "lintfix": "npm run lint -- --fix",
+    "snap": "tap test/ --100 --timeout=30",
+    "posttest": "npm run lint"
+  },
+  "devDependencies": {
+    "@npmcli/template-oss": "4.17.0",
+    "tap": "^12.7.0"
+  },
+  "license": "ISC",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/npm/node-semver.git"
+  },
+  "bin": {
+    "semver": "./bin/semver.js"
+  },
+  "files": [
+    "bin",
+    "range.bnf",
+    "semver.js"
+  ],
+  "author": "GitHub Inc.",
+  "templateOSS": {
+    "//@npmcli/template-oss": "This file is partially managed by @npmcli/template-oss. Edits may be overwritten.",
+    "content": "./scripts/template-oss",
+    "version": "4.17.0"
+  }
+}