semi implemented and features implemented save checkpoint

docs/features/unchecked/releaseorchestrator/multi-region-federation-system.md

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+# Multi-Region Federation System (Sync, Replication, Routing, Dashboard)
+
+## Module
+ReleaseOrchestrator
+
+## Status
+IMPLEMENTED
+
+## Description
+Federation hub for geographically distributed deployments: cross-region data sync with vector clock-based conflict resolution (KeepLocal/KeepRemote/Merge/LastWriteWins), global promotion orchestration (Sequential/Canary/Parallel/BlueGreen strategies), evidence replication with data residency compliance (GDPR/sovereignty), latency-based region routing with automatic probing, and global dashboard with cross-region visibility, alert management, and sync status.
+
+## Implementation Details
+- **Modules**: `src/ReleaseOrchestrator/__Libraries/StellaOps.ReleaseOrchestrator.Federation/`
+- **Key Classes**:
+  - `FederationHub` (`src/ReleaseOrchestrator/__Libraries/StellaOps.ReleaseOrchestrator.Federation/FederationHub.cs`) - background service coordinating cross-region federation
+  - `CrossRegionSync` (`src/ReleaseOrchestrator/__Libraries/StellaOps.ReleaseOrchestrator.Federation/CrossRegionSync.cs`) - data synchronization across regions with vector clock conflict resolution
+  - `RegionCoordinator` (`src/ReleaseOrchestrator/__Libraries/StellaOps.ReleaseOrchestrator.Federation/RegionCoordinator.cs`) - orchestrates global promotions (Sequential/Canary/Parallel/BlueGreen strategies)
+  - `GlobalDashboard` (`src/ReleaseOrchestrator/__Libraries/StellaOps.ReleaseOrchestrator.Federation/GlobalDashboard.cs`) - cross-region visibility, alert management, and sync status
+- **Interfaces**: `ICrossRegionSync`, `IRegionCoordinator`, `IGlobalDashboard`
+- **Source**: SPRINT_20260117_036
+
+## E2E Test Plan
+- [ ] Start `FederationHub` and verify it discovers and connects to remote regions
+- [ ] Sync data across two regions via `CrossRegionSync` and verify conflict resolution (KeepLocal, LastWriteWins)
+- [ ] Trigger a global promotion via `RegionCoordinator` with Sequential strategy and verify region-by-region rollout
+- [ ] Verify data residency: sync evidence and confirm GDPR-compliant data stays within designated regions
+- [ ] Query `GlobalDashboard` for cross-region sync status and verify visibility across all regions
+- [ ] Verify latency-based routing: probe regions and confirm routing decisions match latency measurements