ci: add Gitea Actions workflow for build & deploy

Adds CI/CD pipeline that:
- Builds Docker image on push to staging branch
- Pushes to GHCR
- Deploys to Swarm service

.gitea/workflows/build-deploy.yml

@@ -0,0 +1,38 @@
+name: Build & Deploy Mobile
+on:
+  push:
+    branches:
+      - staging
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: maifors/falah-mobile
+  SWARM_SERVICE: falah_falah-mobile
+
+jobs:
+  build-and-deploy:
+    runs-on: contabo
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Log in to Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ secrets.REGISTRY_USERNAME }}
+          password: ${{ secrets.REGISTRY_PASSWORD }}
+
+      - name: Build and Push Docker Image
+        run: |
+          IMAGE_TAG="${REGISTRY}/${IMAGE_NAME}:staging-${GITHUB_SHA::7}"
+          docker build -t ${IMAGE_TAG} -t ${REGISTRY}/${IMAGE_NAME}:staging .
+          docker push ${IMAGE_TAG}
+          docker push ${REGISTRY}/${IMAGE_NAME}:staging
+
+      - name: Deploy to Swarm
+        run: |
+          docker service update \
+            --image ${REGISTRY}/${IMAGE_NAME}:staging \
+            --with-registry-auth \
+            ${SWARM_SERVICE}