ci: restore github pages deploy workflow

Accidentally removed in 4abbb57 (stash-pop conflict resolution) alongside
oma-agent harness files under .github/. Restores auto-deploy to
firstfluke.com on push to main.

Author: gahyun-git

.github/workflows/deploy.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: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: 1.3.5
+
+      - run: bun install --frozen-lockfile
+
+      - run: bun run build
+        env:
+          NEXT_TELEMETRY_DISABLED: "1"
+          NEXT_PUBLIC_CONTACT_API_URL: ${{ vars.NEXT_PUBLIC_CONTACT_API_URL }}
+
+      - uses: actions/configure-pages@v5
+        with:
+          enablement: true
+
+      - run: touch out/.nojekyll
+
+      - 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