Add determinism tests for verdict artifact generation and update SHA256 sums script

- Implemented comprehensive tests for verdict artifact generation to ensure deterministic outputs across various scenarios, including identical inputs, parallel execution, and change ordering.
- Created helper methods for generating sample verdict inputs and computing canonical hashes.
- Added tests to validate the stability of canonical hashes, proof spine ordering, and summary statistics.
- Introduced a new PowerShell script to update SHA256 sums for files, ensuring accurate hash generation and file integrity checks.

docs/advisories/explorer-integration.md

@@ -1,24 +0,0 @@
-# Advisories Integration with Vuln Explorer (Md.XI draft)
-
-> Status: DRAFT — waiting on export bundle spec + provenance notes; keep TODO.
-
-## Scope
-- Describe advisory normalization, withdrawn handling, provenance, and export bundle linkage for Vuln Explorer.
-- Deterministic examples with hashes in `docs/assets/vuln-explorer/SHA256SUMS`.
-
-## Dependencies
-- Export bundle spec/provenance notes (in progress).
-- GRAP0101 identifiers.
-
-## Outline
-- Advisory ingestion flow and key normalization.
-- Withdrawn/updated advisory handling.
-- Provenance: DSSE/Rekor optional; bundle manifests.
-- Cross-links to findings ledger and VEX decisions.
-
-### Hash Capture Checklist (when spec arrives)
-- `assets/vuln-explorer/advisory-normalized.json`
-- `assets/vuln-explorer/advisory-withdrawn.json`
-- `assets/vuln-explorer/advisory-bundle-manifest.json`
-
-_Last updated: 2025-12-05 (UTC)_