Add Forgejo deploy workflow

.forgejo/workflows/deploy.yml

@@ -0,0 +1,28 @@
+name: Deploy
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      # The job container only sees its own checkout — the live app lives
+      # at /mnt/user/appdata/greendale on the host, bind-mounted into this
+      # container at the same path (see runner container.options) so
+      # `docker compose`'s relative paths resolve against the real host
+      # directory rather than an ephemeral one. `.env` is server-only and
+      # must survive every deploy.
+      - name: Sync source to deploy path
+        run: |
+          rsync -a --delete \
+            --exclude='.git' \
+            --exclude='.env' \
+            ./ /mnt/user/appdata/greendale/
+
+      - name: Rebuild and restart
+        working-directory: /mnt/user/appdata/greendale
+        run: docker compose up -d --build