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/observability/vuln-telemetry.md

@@ -1,23 +0,0 @@
-# Vuln Telemetry (Md.XI draft)
-
-> Status: DRAFT — waiting on DevOps telemetry plan and GRAP0101. Keep TODO until metrics/logs finalized and hashed.
-
-## Scope
-- Metrics, logs, tracing, dashboards, SLOs for Vuln Explorer.
-
-## Dependencies
-- DevOps telemetry plan (due 2025-12-16 sync).
-- GRAP0101 identifiers for labels.
-
-## Outline
-- Metrics: findings_open_total, mttr, triage_actions, report_generation_seconds.
-- Logs: structured fields (findingId, artifactId, advisory, policyVersion, actor, actionType).
-- Traces: key spans; sampling guidance.
-- Dashboards: to be added with hashes.
-
-### Hash Capture Checklist (when telemetry plan arrives)
-- `assets/vuln-explorer/metrics-sample.json` (scrape example)
-- `assets/vuln-explorer/logs-sample.jsonl` (structured log snippet)
-- `assets/vuln-explorer/traces-sample.json` (span export)
-- `assets/vuln-explorer/dashboard.json` (dashboard export)
-_Last updated: 2025-12-05 (UTC)_