feat(deploy): add GitHub Actions workflow for backend deployment

.gitea/workflows/deploy.yml

@@ -0,0 +1,43 @@
+name: Deploy Backend
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  deploy:
+    runs-on: linux
+    defaults:
+      run:
+        working-directory: /home/app/saude/service-user
+
+    steps:
+      - name: Install SSH
+        run: |
+          if command -v apk >/dev/null; then
+            apk add --no-cache openssh-client
+          elif command -v apt-get >/dev/null; then
+            apt-get update && apt-get install -y openssh-client
+          fi
+
+      - name: Install Node
+        run: apk add --no-cache nodejs npm
+
+      - name: Pull latest source from main
+        run: |
+          git fetch origin
+          git reset --hard origin/main
+
+      - name: Install deps
+        run: npm install
+
+      - name: Build
+        run: |
+          export NODE_ENV=stag
+          npm run swagger
+          npm run build
+
+      - name: Reload PM2
+        run: |
+          ssh -o StrictHostKeyChecking=no root@172.21.0.1 "/usr/bin/pm2 reload saude-svc-user || /usr/bin/pm2 start /home/app/saude/ecosystem.config.js --only saude-svc-user"