# Snapshot Merge Preview with K4 Lattice Visualization and Determinism Verification

## Module
Web

## Status
VERIFIED

## Description
Snapshot management UI with merge preview showing per-CVE source contributions with trust scores, K4 lattice visualization, merge traces, missing evidence indicators, REPLAY.yaml format for deterministic replay, and verify-determinism component. (Merged with Snapshot Merge Preview from Phase 2 AirGap section.)

## Implementation Details
- **Feature directories**:
  - `src/Web/StellaOps.Web/src/app/shared/components/lattice-diagram/`
  - `src/Web/StellaOps.Web/src/app/features/snapshot/components/merge-preview/`
  - `src/Web/StellaOps.Web/src/app/features/snapshot/components/verify-determinism/`
  - `src/Web/StellaOps.Web/src/app/features/snapshot/components/snapshot-panel/`
- **Components**:
  - `lattice-diagram` (`src/Web/StellaOps.Web/src/app/shared/components/lattice-diagram/lattice-diagram.component.ts`)
  - `merge-preview` (`src/Web/StellaOps.Web/src/app/features/snapshot/components/merge-preview/merge-preview.component.ts`)
  - `verify-determinism` (`src/Web/StellaOps.Web/src/app/features/snapshot/components/verify-determinism/verify-determinism.component.ts`)
  - `snapshot-panel` (`src/Web/StellaOps.Web/src/app/features/snapshot/components/snapshot-panel/snapshot-panel.component.ts`)
- **Source**: Feature matrix scan

## E2E Test Plan
- **Setup**:
  - [ ] Log in with a user that has appropriate permissions
  - [ ] Navigate to the relevant page/section where this feature appears
  - [ ] 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)

## Verification
- Run ID: `docs/qa/feature-checks/runs/web/snapshot-merge-preview-with-k4-lattice-visualization-and-determinism-verificatio/run-001/`
- Date (UTC): 2026-02-11
- Tier 0: PASS (source/symbol verification for lattice, merge-preview, verify-determinism, snapshot-panel, and supported behavior spec).
- Tier 1: PASS (`npm run test` focused suite: 16 files / 78 tests; `npm run build` passed with known baseline warnings).
- Tier 2: PASS (behavioral verification of K4 lattice semantics, merge preview interactions, determinism API success/error paths, and REPLAY manifest/export actions).