feat: add GitHub Pages deployment with custom domain

- GitHub Actions workflow builds Vite app and deploys to Pages
- CNAME file for form.ideenparc.net custom domain

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: deni-commits

.github/workflows/deploy.yml

@@ -0,0 +1,47 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches: [main]
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+          cache-dependency-path: positionierungscheck/package-lock.json
+
+      - name: Install & Build
+        working-directory: positionierungscheck
+        run: |
+          npm ci
+          npm run build
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v5
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: positionierungscheck/dist
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

positionierungscheck/public/CNAME

@@ -0,0 +1 @@
+form.ideenparc.net