feat: add CI/CD workflow and switch to bind mount for data

Use a Gitea Actions workflow to deploy on push to main via
act_runner on the games VM. Switch from a Docker named volume
to a ./data bind mount for easier backup and persistence across
deploys.

.gitea/workflows/deploy.yml

@@ -0,0 +1,22 @@
+name: Deploy c4
+
+on:
+  push:
+    branches: [main]
+
+env:
+  DEPLOY_DIR: /home/ryan/c4
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Sync to deploy directory
+        run: |
+          mkdir -p $DEPLOY_DIR
+          rsync -a --delete --exclude 'data/' . $DEPLOY_DIR/
+
+      - name: Rebuild and restart
+        run: cd $DEPLOY_DIR && docker compose up -d --build --remove-orphans