Add tests and implement StubBearer authentication for Signer endpoints

- Created SignerEndpointsTests to validate the SignDsse and VerifyReferrers endpoints.
- Implemented StubBearerAuthenticationDefaults and StubBearerAuthenticationHandler for token-based authentication.
- Developed ConcelierExporterClient for managing Trivy DB settings and export operations.
- Added TrivyDbSettingsPageComponent for UI interactions with Trivy DB settings, including form handling and export triggering.
- Implemented styles and HTML structure for Trivy DB settings page.
- Created NotifySmokeCheck tool for validating Redis event streams and Notify deliveries.

docs/updates/2025-10-20-authority-identity-registry.md

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+# 2025-10-20 — Authority Identity Provider Registry & DPoP nonce updates
+
+## Summary
+- Authority host now resolves identity providers through the new metadata/handle pattern introduced in `StellaOps.Authority.Plugins.Abstractions`. Runtime handlers (`ValidateClientCredentialsHandler`, `ValidatePasswordGrantHandler`, `ValidateAccessTokenHandler`, bootstrap endpoints) acquire providers with `IAuthorityIdentityProviderRegistry.AcquireAsync` and rely on metadata (`AuthorityIdentityProviderMetadata`) for capability checks.
+- Unit and integration tests build lightweight `ServiceProvider` instances with test plugins, matching production DI behaviour and ensuring the new registry contract is exercised.
+- DPoP nonce enforcement now prefers `NormalizedAudiences` when populated and gracefully falls back to the configured `RequiredAudiences`, eliminating the runtime type mismatch that previously surfaced during test runs.
+
+## Operator impact
+- No configuration changes are required; existing YAML and environment-based settings continue to function.
+- Documentation examples referencing password/mTLS bootstrap flows remain accurate. The new registry logic simply ensures providers advertised in configuration are resolved deterministically and capability-gated before use.
+
+## Developer notes
+- When adding new identity providers or tests, register plugins via `ServiceCollection` and call `new AuthorityIdentityProviderRegistry(serviceProvider, logger)`.
+- For DPoP-required endpoints, populate `security.senderConstraints.dpop.nonce.requiredAudiences` or rely on defaults; both now funnel through the normalized set.

docs/updates/2025-10-20-scanner-events.md

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+# 2025-10-20 – Scanner Platform Events Hardening
+
+- Scanner WebService now wires a reusable `IRedisConnectionFactory`, simplifying redis transport testing and reuse for future adapters.
+- `/api/v1/reports` integration test (`ReportsEndpointPublishesPlatformEvents`) asserts both report-ready and scan-completed envelopes carry DSSE payloads, scope metadata, and deterministic verdicts.
+- Task `SCANNER-EVENTS-15-201` closed after verifying `dotnet test src/StellaOps.Scanner.WebService.Tests/StellaOps.Scanner.WebService.Tests.csproj`.