# Approval Gateway with Multi-Approver and Separation of Duties

## Module
ReleaseOrchestrator

## Status
IMPLEMENTED

## Description
Approval workflow engine enforcing separation of duties (requester != approver), multi-approver requirements (N of M), group-based eligibility checking, approval history tracking, notification integration, and governance controls for release promotions.

## Implementation Details
- **Modules**: `src/ReleaseOrchestrator/__Libraries/StellaOps.ReleaseOrchestrator.Promotion/Approval/`
- **Key Classes**:
  - `ApprovalGateway` (`src/ReleaseOrchestrator/__Libraries/StellaOps.ReleaseOrchestrator.Promotion/Approval/ApprovalGateway.cs`) - approval workflow engine with multi-approver and group eligibility
  - `SeparationOfDutiesEnforcer` (`src/ReleaseOrchestrator/__Libraries/StellaOps.ReleaseOrchestrator.Promotion/Approval/SeparationOfDutiesEnforcer.cs`) - enforces requester != approver constraint
- **Interfaces**: `IApprovalGateway`, `ISeparationOfDutiesEnforcer`
- **Source**: SPRINT_20260110_106_002_PROMOT_approval_gateway.md

## E2E Test Plan
- [ ] Submit an approval request and verify `SeparationOfDutiesEnforcer` rejects the requester from self-approving
- [ ] Verify multi-approver: configure N of M requirement and verify approval is granted only after N approvals
- [ ] Verify group eligibility: configure group-based approval and verify only group members can approve
- [ ] Verify approval history: approve a request and confirm the approval record is persisted with timestamps
- [ ] Verify rejection: deny an approval and confirm the promotion is blocked