Add GitHub Actions workflow for auto-deploy to Fly.io

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/deploy.yml

@@ -0,0 +1,14 @@
+name: Deploy to Fly.io
+on:
+  push:
+    branches: [main]
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: superfly/flyctl-actions/setup-flyctl@master
+      - run: flyctl deploy --remote-only
+        env:
+          FLY_API_TOKEN: ${{ secrets.FLY_API_TOKEN }}