feat: add Reachability Center and Why Drawer components with tests

- Implemented ReachabilityCenterComponent for displaying asset reachability status with summary and filtering options.
- Added ReachabilityWhyDrawerComponent to show detailed reachability evidence and call paths.
- Created unit tests for both components to ensure functionality and correctness.
- Updated accessibility test results for the new components.

docs/api/gateway/samples/advisory-ai-start-job-response.json

@@ -0,0 +1,26 @@
+{
+  "jobId": "aiai-job-0001",
+  "status": "queued",
+  "traceId": "trace-fixture-aiai",
+  "createdAt": "2025-12-03T00:00:00Z",
+  "guardrail": {
+    "blocked": false,
+    "state": "ok",
+    "violations": [],
+    "metadata": {
+      "blockedPhraseFile": "configs/guardrails/blocked-phrases.json",
+      "blocked_phrase_count": 0,
+      "promptLength": 0,
+      "planFromCache": false,
+      "promptHash": "sha256:0000000000000000",
+      "telemetryCounters": {
+        "advisory_ai_guardrail_blocks_total": 0,
+        "advisory_ai_chunk_cache_hits_total": 0
+      },
+      "links": {
+        "logs": "/audit/advisory-ai/runs/2025-12-03T00:00:00Z"
+      }
+    }
+  }
+}
+