feat: add Cloudflare Pages deployment support

next.config.mjs now detects CF_PAGES=1 (auto-injected by Cloudflare during
build) and switches basePath from /loto to "" — assets resolve at the
project root on loto.pages.dev. GH Pages keeps /loto unchanged.

New workflow .github/workflows/deploy-cloudflare-pages.yml mirrors the GH
Pages flow but publishes via cloudflare/wrangler-action@v3. Requires repo
secrets CLOUDFLARE_API_TOKEN and CLOUDFLARE_ACCOUNT_ID; project name "loto"
is hardcoded — adjust --project-name= in the workflow if your CF Pages
project uses a different name.

Dashboard-based deploys also work without code changes thanks to the
CF_PAGES detection. See docs/deployment-guide.md for both paths.

.github/workflows/deploy-cloudflare-pages.yml

@@ -0,0 +1,36 @@
+name: Deploy to Cloudflare Pages
+
+on:
+  push:
+    branches: [master]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  deployments: write
+
+concurrency:
+  group: cf-pages
+  cancel-in-progress: true
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+      - run: npm ci
+      - run: npm run build
+        env:
+          # Force root basePath: CF Pages serves the site at the project root
+          # (loto.pages.dev), unlike GH Pages which prefixes with /loto.
+          NEXT_BASE_PATH: ""
+      - name: Publish to Cloudflare Pages
+        uses: cloudflare/wrangler-action@v3
+        with:
+          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
+          accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
+          command: pages deploy out --project-name=loto --branch=${{ github.ref_name }}