feat: add GitHub Pages deployment workflow

Configure static export and GitHub Actions workflow
to auto-deploy to GitHub Pages on push to master.

web/.github/workflows/deploy.yml

@@ -0,0 +1,40 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches: [master]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+      - run: npm ci
+      - run: npx next build
+      - uses: actions/upload-pages-artifact@v3
+        with:
+          path: out
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - id: deployment
+        uses: actions/deploy-pages@v4

web/next.config.ts

@@ -1,7 +1,8 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  /* config options here */
+  output: "export",
+  basePath: "/loto",
 };
 
 export default nextConfig;