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.

deploy/compose/env/airgap.env.example

@@ -10,8 +10,15 @@ SIGNER_POE_INTROSPECT_URL=file:///offline/poe/introspect.json
 SIGNER_PORT=8441
 ATTESTOR_PORT=8442
 CONCELIER_PORT=8445
-SCANNER_WEB_PORT=8444
-UI_PORT=9443
-NATS_CLIENT_PORT=24222
-SCANNER_QUEUE_BROKER=nats://nats:4222
-AUTHORITY_OFFLINE_CACHE_TOLERANCE=00:45:00
+SCANNER_WEB_PORT=8444
+UI_PORT=9443
+NATS_CLIENT_PORT=24222
+SCANNER_QUEUE_BROKER=nats://nats:4222
+AUTHORITY_OFFLINE_CACHE_TOLERANCE=00:45:00
+SCANNER_EVENTS_ENABLED=false
+SCANNER_EVENTS_DRIVER=redis
+# Leave SCANNER_EVENTS_DSN empty to inherit the Redis queue DSN when SCANNER_QUEUE_BROKER uses redis://.
+SCANNER_EVENTS_DSN=
+SCANNER_EVENTS_STREAM=stella.events
+SCANNER_EVENTS_PUBLISH_TIMEOUT_SECONDS=5
+SCANNER_EVENTS_MAX_STREAM_LENGTH=10000