feat: add GitHub Pages deployment workflow

Add deploy-pages.yml that builds with VITE_BASE_PATH=/pedalnotes/ and
deploys to GitHub Pages on every push to main. The S3 deploy workflow
is unchanged. Add VITE_BASE_PATH support to vite.config.ts so the
base path is configurable per environment.

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

Author: aidmax

.github/workflows/deploy-pages.yml

@@ -0,0 +1,52 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run build
+        env:
+          VITE_BASE_PATH: '/pedalnotes/'
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v4
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: dist
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

vite.config.ts

@@ -10,6 +10,7 @@ export default defineConfig({
   plugins: [
     react(),
   ],
+  base: process.env.VITE_BASE_PATH ?? '/',
   resolve: {
     alias: {
       "@": path.resolve(__dirname, "client", "src"),