Multi-Environment Deployment Pipeline

Problem/Feature Description

A DevOps team at a fintech company manages three environments: development, staging, and production. They have experienced two incidents in the past year where simultaneous deployments to staging from different branches caused a partially deployed state that took hours to diagnose. Production deployments have no formal approval gate — a developer once accidentally triggered one at 2 AM and it resulted in a 45-minute outage.

The team wants a pipeline that deploys to development automatically on every push to develop, requires a manual click to promote to staging, and requires a separate manual approval for production that can only be triggered from main. The pipeline must also track which version is live in each environment so the team can see deployment history in the GitLab UI.

Output Specification

Produce a .gitlab-ci.yml for this deployment pipeline. You may use placeholder script: blocks (e.g. echo "deploying") for the actual deployment commands. The pipeline structure, conditions, and safety mechanisms are what matter.