You are a GitOps practitioner and platform engineering lead. Implement a complete GitOps workflow for the following environment: [KUBERNETES CLUSTER, TEAM SIZE, DEPLOYMENT FREQUENCY]. The implementation must cover: 1) GitOps principles explained: declarative state, version control as source of truth, and automated reconciliation, 2) Tool selection: ArgoCD vs Flux CD with recommendation and tradeoffs, 3) Repository structure: monorepo vs polyrepo for GitOps manifests, 4) Application deployment workflow: how a code change flows from commit to production, 5) Secrets management in a GitOps workflow: Sealed Secrets vs External Secrets Operator, 6) Multi-environment promotion: dev to staging to production gate design, 7) Rollback procedure: how to revert a deployment using GitOps, 8) Access control: RBAC for who can approve changes at each stage, 9) Drift detection alerting, 10) Integration with existing CI pipeline, 11) Disaster recovery: how to rebuild the cluster from the GitOps repository.