feat(deploy): add Jenkins production deployment pipeline

docs/deployment-production.md

@@ -56,3 +56,66 @@ Before deploying, set production-safe values in `.env` (using `.env.example` as
 - cron/job shared secrets
 
 Keep secrets out of source control.
+
+## Jenkins pipeline flow
+
+The repository includes a declarative `Jenkinsfile` with the following stages:
+
+1. **Checkout**
+2. **Install dependencies** (`npm ci`)
+3. **Lint** (runs only when `package.json` contains a `lint` script)
+4. **Build application** (`npm run build`)
+5. **Build Docker image** (tags `latest` and `build-${BUILD_NUMBER}`)
+6. **Deploy** over SSH to the app host
+7. **Smoke check** against `/api/health`
+
+## Required Jenkins configuration
+
+Configure these values in Jenkins job/folder/global environment or credentials-backed environment variables:
+
+- `DEPLOY_SSH_HOST` - remote app host
+- `DEPLOY_SSH_USER` - SSH user on remote host
+- `DEPLOY_SSH_CREDENTIAL_ID` - Jenkins SSH Agent credential ID
+- `DEPLOY_PATH` - remote deployment path (for example `/opt/plesk-agency-portal`)
+- `APP_BASE_URL` - externally reachable app URL used by smoke check
+
+The pipeline assumes Jenkins credentials are managed outside this repository.
+
+## Deploy flow
+
+Deployment is intentionally simple and bash-based:
+
+1. Jenkins builds Docker image tags locally.
+2. Jenkins syncs deployment files (`docker-compose.prod.yml`, deploy/smoke/rollback scripts) to the remote deploy path.
+3. Jenkins streams Docker images to the remote host (`docker save | ssh docker load`).
+4. Jenkins runs `scripts/deploy-prod.sh` remotely.
+5. Script applies the selected image tag via:
+
+```bash
+APP_IMAGE=<tag> docker compose -f docker-compose.prod.yml up -d --no-build
+```
+
+6. Script prints `docker compose ps` status.
+
+## Rollback flow
+
+Rollback uses `scripts/rollback-prod.sh` with a previously built image tag:
+
+```bash
+DEPLOY_PATH=/opt/plesk-agency-portal \
+APP_BASE_URL=https://your-app.example.com \
+scripts/rollback-prod.sh plesk-agency-portal:build-123
+```
+
+Rollback redeploys that image with compose, then immediately reruns smoke checks.
+
+## Smoke check behavior
+
+`scripts/smoke-check.sh`:
+
+- accepts a base URL argument
+- requests `${BASE_URL}/api/health`
+- fails on non-200 responses
+- fails on invalid JSON or missing expected fields (`ok: true`, `service` string)
+
+This gives a quick post-deploy validation gate for both deploy and rollback operations.