Enable production API Gateway auto deploy

[riddim-developer-bot]

What changed

• Add a production API Gateway activation job to backend-production.yml.
• Enable auto-deploy for the production HTTP API stage after production route provisioning jobs run.

Why

Production API Gateway has AutoDeploy disabled, so newly created workflow-managed routes can exist in API Gateway but still return 404 through the production custom domain until the stage is manually deployed. The lobbying organization detail routes are already present in the manifest, and rerunning promotion after this change will create and activate them.

Testing

• actionlint .github/workflows/backend-production.yml
• Confirmed manifest includes production organization detail routes:
  • GET /api/v1/lobbying/organizations/{id}
  • GET /lobbying/organizations/{id}