chore: set up github workflow

Author: nozomuikuta

.github/workflows/deploy.yml

@@ -0,0 +1,33 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: withastro/action@v3
+        with:
+          path: .
+          node-version: 22
+          # `package-manager` option is determined by `packageManager` in `package.json`
+
+  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

astro.config.mjs

@@ -1,5 +1,14 @@
 // @ts-check
 import { defineConfig } from "astro/config";
 
-// https://astro.build/config
-export default defineConfig({});
+export default defineConfig({
+  site: "https://gocon.github.io",
+  base: "/2025",
+  i18n: {
+    defaultLocale: "ja",
+    locales: ["ja"],
+    routing: {
+      prefixDefaultLocale: false,
+    },
+  },
+});