feat: Implement vulnerability token signing and verification utilities

- Added VulnTokenSigner for signing JWT tokens with specified algorithms and keys.
- Introduced VulnTokenUtilities for resolving tenant and subject claims, and sanitizing context dictionaries.
- Created VulnTokenVerificationUtilities for parsing tokens, verifying signatures, and deserializing payloads.
- Developed VulnWorkflowAntiForgeryTokenIssuer for issuing anti-forgery tokens with configurable options.
- Implemented VulnWorkflowAntiForgeryTokenVerifier for verifying anti-forgery tokens and validating payloads.
- Added AuthorityVulnerabilityExplorerOptions to manage configuration for vulnerability explorer features.
- Included tests for FilesystemPackRunDispatcher to ensure proper job handling under egress policy restrictions.

src/Attestor/StellaOps.Attestor/TASKS.md

@@ -29,7 +29,7 @@
 ### Sprint 74 – Transparency & Bulk
 | ID | Status | Owner(s) | Depends on | Description | Exit Criteria |
 |----|--------|----------|------------|-------------|---------------|
-| ATTESTOR-74-001 | DONE (2025-11-02) | Attestor Service Guild | ATTESTOR-73-002, TRANSP-74-001 | Integrate transparency witness client, inclusion proof verification, and caching. | Witness proofs stored; verification fails on missing/inconsistent proofs; metrics emitted. |
+| ATTESTOR-74-001 | DONE (2025-11-02) | Attestor Service Guild | ATTESTOR-73-002, TRANSP-74-001 | Integrate transparency witness client, inclusion proof verification, and caching.<br>2025-11-02: Witness client wired with repository schema update; verification/reporting paths refreshed and test suite green. | Witness proofs stored; verification fails on missing/inconsistent proofs; metrics emitted. |
 | ATTESTOR-74-002 | DONE | Attestor Service Guild | ATTESTOR-73-002 | Implement bulk verification worker + API with progress tracking, rate limits, and caching. | Bulk job API functional; worker processes batches; telemetry recorded. |
 
 ### Sprint 75 – Air Gap & Hardening