feat(zastava): add evidence locker plan and schema examples

- Introduced README.md for Zastava Evidence Locker Plan detailing artifacts to sign and post-signing steps.
- Added example JSON schemas for observer events and webhook admissions.
- Updated implementor guidelines with checklist for CI linting, determinism, secrets management, and schema control.
- Created alert rules for Vuln Explorer to monitor API latency and projection errors.
- Developed analytics ingestion plan for Vuln Explorer, focusing on telemetry and PII guardrails.
- Implemented Grafana dashboard configuration for Vuln Explorer metrics visualization.
- Added expected projection SHA256 for vulnerability events.
- Created k6 load testing script for Vuln Explorer API.
- Added sample projection and replay event data for testing.
- Implemented ReplayInputsLock for deterministic replay inputs management.
- Developed tests for ReplayInputsLock to ensure stable hash computation.
- Created SurfaceManifestDeterminismVerifier to validate manifest determinism and integrity.
- Added unit tests for SurfaceManifestDeterminismVerifier to ensure correct functionality.
- Implemented Angular tests for VulnerabilityHttpClient and VulnerabilityDetailComponent to verify API interactions and UI rendering.

docs/modules/zastava/kit/verify.sh

@@ -8,7 +8,17 @@ if ! command -v sha256sum >/dev/null; then
 fi
 
 sha256sum --check SHA256SUMS
-# TODO: add DSSE verification once signatures are available; placeholder below
-# cosign verify-blob --key cosign.pub --signature observer_event.schema.json.sig observer_event.schema.json
+if command -v cosign >/dev/null && [ -f cosign.pub ]; then
+  echo "cosign present; DSSE verification placeholders (update paths when signed):"
+  echo "- observer_event.schema.dsse"
+  echo "- webhook_admission.schema.dsse"
+  echo "- thresholds.dsse"
+  # Example commands (uncomment once DSSE files exist):
+  # cosign verify-blob --key cosign.pub --signature observer_event.schema.dsse schemas/observer_event.schema.json
+  # cosign verify-blob --key cosign.pub --signature webhook_admission.schema.dsse schemas/webhook_admission.schema.json
+  # cosign verify-blob --key cosign.pub --signature thresholds.dsse thresholds.yaml
+else
+  echo "cosign not found or cosign.pub missing; skipped DSSE verification"
+fi
 
 echo "OK: hashes verified (DSSE verification pending)"