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/leaflet.offline/.github/workflows/docs.yml

@@ -0,0 +1,33 @@
+name: Update docs site
+
+on: workflow_dispatch
+permissions:  
+  contents: write # for checkout
+  pages: write
+
+jobs:
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v2
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v2
+        with:
+          node-version: 22
+
+      - name: Install Dependencies
+        run: npm ci
+
+      - name: Build Docs
+        run: npm run docs:build  
+
+      - name: Deploy with gh-pages
+        run: |
+          git remote set-url origin https://git:${GITHUB_TOKEN}@github.com/${GITHUB_REPOSITORY}.git
+          npm run docs:deploy -- -u "github-actions-bot <support+actions@github.com>"
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}