feat: Implement policy attestation features and service account delegation

- Added new policy scopes: `policy:publish` and `policy:promote` with interactive-only enforcement.
- Introduced metadata parameters for policy actions: `policy_reason`, `policy_ticket`, and `policy_digest`.
- Enhanced token validation to require fresh authentication for policy attestation tokens.
- Updated grant handlers to enforce policy scope checks and log audit information.
- Implemented service account delegation configuration, including quotas and validation.
- Seeded service accounts during application initialization based on configuration.
- Updated documentation and tasks to reflect new features and changes.

docs/TASKS.md

@@ -24,6 +24,20 @@
 | ID | Status | Owner(s) | Depends on | Description | Exit Criteria |
 |----|--------|----------|------------|-------------|---------------|
 | DOCS-SCANNER-BENCH-62-001 | DONE (2025-11-02) | Docs Guild, Scanner Guild | — | Maintain scanner comparison docs for Trivy, Grype, and Snyk; refresh deep dives and ecosystem matrix with source-linked implementation notes. | Comparison docs updated; matrix synced; deep dives cite source paths and highlight coverage gaps. |
+| DOCS-SCANNER-BENCH-62-002 | TODO | Docs Guild, Product Guild | DOCS-SCANNER-BENCH-62-001 | Collect Windows/macOS analyzer demand signals per `docs/benchmarks/scanner/windows-macos-demand.md`. | Demand summary produced; intake form updated; design spike criteria evaluated. |
+| DOCS-SCANNER-BENCH-62-003 | TODO | Docs Guild, Product Guild | DOCS-SCANNER-BENCH-62-002 | Capture Python lockfile / editable install requirements and document policy guidance once design completes. | Demand notes merged; policy template drafted. |
+| DOCS-SCANNER-BENCH-62-004 | TODO | Docs Guild, Java Analyzer Guild | DOCS-SCANNER-BENCH-62-003 | Document Java lockfile ingestion plan and associated policy templates per `scanning-gaps-stella-misses-from-competitors.md`. | Draft guidance published; policy examples reviewed. |
+| DOCS-SCANNER-BENCH-62-005 | TODO | Docs Guild, Go Analyzer Guild | DOCS-SCANNER-BENCH-62-004 | Document Go stripped-binary fallback enrichment guidance once implementation lands. | Docs updated with inferred module policy patterns. |
+| DOCS-SCANNER-BENCH-62-006 | TODO | Docs Guild, Rust Analyzer Guild | DOCS-SCANNER-BENCH-62-005 | Document Rust fingerprint enrichment guidance and policy examples. | Docs cover heuristic vs authoritative crate handling. |
+| DOCS-SCANNER-BENCH-62-007 | TODO | Docs Guild, Security Guild | DOCS-SCANNER-BENCH-62-006 | Produce secret leak detection documentation (rules, policy templates) once implementation lands. | Docs include rule bundle guidance and policy patterns. |
+| DOCS-SCANNER-BENCH-62-008 | TODO | Docs Guild, EntryTrace Guild | DOCS-SCANNER-BENCH-62-007 | Publish EntryTrace explain/heuristic maintenance guide per `scanning-gaps-stella-misses-from-competitors.md`. | Guide covers cadence, contribution workflow, and policy predicates. |
+| DOCS-SCANNER-BENCH-62-009 | DONE (2025-11-02) | Docs Guild, Ruby Analyzer Guild | DOCS-SCANNER-BENCH-62-008 | Extend Ruby ecosystem gap analysis in `scanning-gaps-stella-misses-from-competitors.md` with implementation notes, detection tables, and backlog mapping. | Ruby section updated with competitor techniques, task linkage, and scoring rationale. |
+| DOCS-SCANNER-BENCH-62-010 | DONE (2025-11-02) | Docs Guild, PHP Analyzer Guild | DOCS-SCANNER-BENCH-62-009 | Document PHP analyzer parity gaps with detection technique tables and policy hooks. | PHP section merged with plan references and backlog linkage. |
+| DOCS-SCANNER-BENCH-62-011 | DONE (2025-11-02) | Docs Guild, Language Analyzer Guild | DOCS-SCANNER-BENCH-62-010 | Capture Deno runtime gap analysis versus competitors, including detection/merge strategy table. | Deno section added with implementation notes and backlog callouts. |
+| DOCS-SCANNER-BENCH-62-012 | DONE (2025-11-02) | Docs Guild, Language Analyzer Guild | DOCS-SCANNER-BENCH-62-011 | Add Dart ecosystem comparison and task linkage in `scanning-gaps-stella-misses-from-competitors.md`. | Dart section present with detection table, backlog references, and scoring. |
+| DOCS-SCANNER-BENCH-62-013 | DONE (2025-11-02) | Docs Guild, Swift Analyzer Guild | DOCS-SCANNER-BENCH-62-012 | Expand Swift coverage analysis with implementation techniques and policy considerations. | Swift section integrated with detection table and backlog references. |
+| DOCS-SCANNER-BENCH-62-014 | DONE (2025-11-02) | Docs Guild, Runtime Guild | DOCS-SCANNER-BENCH-62-013 | Detail Kubernetes/VM target coverage gaps and interplay with Zastava/Runtime docs. | Target coverage section merged with detection/merging approach and action items. |
+| DOCS-SCANNER-BENCH-62-015 | DONE (2025-11-02) | Docs Guild, Export Center Guild | DOCS-SCANNER-BENCH-62-014 | Document DSSE/Rekor operator enablement guidance from competitor comparison. | DSSE section aligned with Export Center backlog and detection merge table. |
 
 ## Air-Gapped Mode (Epic 16)
 | ID | Status | Owner(s) | Depends on | Description | Exit Criteria |