semi implemented and features implemented save checkpoint

docs/features/unchecked/web/workflow-visualization-with-time-travel-controls.md

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+# Workflow Visualization with Time-Travel Controls
+
+## Module
+Web
+
+## Status
+IMPLEMENTED
+
+## Description
+DAG-based workflow visualizer with time-travel debugging controls. Users can step forward/backward through workflow execution states, inspect step details at each point in time, view execution logs, and interactively debug release workflows. The time-travel service manages historical state snapshots. (Merged with Workflow Visualization UI Module from Phase 2 Web section.)
+
+## Implementation Details
+- **Feature directory**: `src/Web/StellaOps.Web/src/app/features/workflow-visualization/`
+- **Routes**: `workflow-visualization.routes.ts`
+- **Components**:
+  - `step-detail-panel` (`src/Web/StellaOps.Web/src/app/features/workflow-visualization/components/step-detail-panel/step-detail-panel.component.ts`)
+  - `time-travel-controls` (`src/Web/StellaOps.Web/src/app/features/workflow-visualization/components/time-travel-controls/time-travel-controls.component.ts`)
+  - `workflow-visualizer` (`src/Web/StellaOps.Web/src/app/features/workflow-visualization/components/workflow-visualizer/workflow-visualizer.component.ts`)
+- **Services**:
+  - `time-travel` (`src/Web/StellaOps.Web/src/app/features/workflow-visualization/services/time-travel.service.ts`)
+  - `workflow-visualization` (`src/Web/StellaOps.Web/src/app/features/workflow-visualization/services/workflow-visualization.service.ts`)
+- **Source**: Feature matrix scan
+
+## E2E Test Plan
+- **Setup**:
+  - [ ] Log in with a user that has appropriate permissions
+  - [ ] Navigate to `/release-orchestrator`
+  - [ ] Ensure test data exists (scanned artifacts, SBOM data, or seed data as needed)
+- **Core verification**:
+  - [ ] Verify the visualization renders correctly with sample data
+  - [ ] Verify interactive elements (hover tooltips, click-to-drill-down) work
+  - [ ] Verify the visualization handles empty/minimal data gracefully
+- **Edge cases**:
+  - [ ] Verify graceful handling when backend API is unavailable (error state)
+  - [ ] Verify responsive layout at different viewport sizes
+  - [ ] Verify accessibility (keyboard navigation, screen reader labels, ARIA attributes)