Doctor plugin checks: implement health check classes and documentation

Implement remediation-aware health checks across all Doctor plugin modules
(Agent, Attestor, Auth, BinaryAnalysis, Compliance, Crypto, Environment,
EvidenceLocker, Notify, Observability, Operations, Policy, Postgres, Release,
Scanner, Storage, Vex) and their backing library counterparts (AI, Attestation,
Authority, Core, Cryptography, Database, Docker, Integration, Notify,
Observability, Security, ServiceGraph, Sources, Verification).

Each check now emits structured remediation metadata (severity, category,
runbook links, and fix suggestions) consumed by the Doctor dashboard
remediation panel.

Also adds:
- docs/doctor/articles/ knowledge base for check explanations
- Advisory AI search seed and allowlist updates for doctor content
- Sprint plan for doctor checks documentation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/__Libraries/StellaOps.Doctor.Plugins.Observability/Checks/HealthCheckEndpointsCheck.cs

@@ -115,7 +115,8 @@ public sealed class HealthCheckEndpointsCheck : IDoctorCheck
                 .WithCauses(issues.ToArray())
                 .WithRemediation(r => r
                     .AddManualStep(1, "Configure endpoints", "Set separate /health/ready and /health/live endpoints")
-                    .AddManualStep(2, "Set timeout", "Configure reasonable timeout (5-30 seconds)"))
+                    .AddManualStep(2, "Set timeout", "Configure reasonable timeout (5-30 seconds)")
+                    .WithRunbookUrl("docs/doctor/articles/observability/observability-healthchecks.md"))
                 .WithVerification("stella doctor --check check.observability.healthchecks")
                 .Build();
         }

src/__Libraries/StellaOps.Doctor.Plugins.Observability/Checks/LoggingConfigurationCheck.cs

@@ -89,7 +89,8 @@ public sealed class LoggingConfigurationCheck : IDoctorCheck
                 .WithCauses(issues.ToArray())
                 .WithRemediation(r => r
                     .AddManualStep(1, "Set appropriate level", "Use 'Information' or 'Warning' for production")
-                    .AddManualStep(2, "Enable structured logging", "Configure Serilog or JSON console formatter"))
+                    .AddManualStep(2, "Enable structured logging", "Configure Serilog or JSON console formatter")
+                    .WithRunbookUrl("docs/doctor/articles/observability/observability-logging.md"))
                 .WithVerification("stella doctor --check check.observability.logging")
                 .Build());
         }

src/__Libraries/StellaOps.Doctor.Plugins.Observability/Checks/MetricsCollectionCheck.cs

@@ -118,7 +118,8 @@ public sealed class MetricsCollectionCheck : IDoctorCheck
                 .WithCauses(issues.ToArray())
                 .WithRemediation(r => r
                     .AddManualStep(1, "Enable metrics", "Configure Metrics:Enabled or Prometheus:Enabled")
-                    .AddManualStep(2, "Check endpoint", $"curl http://localhost:{metricsPort ?? 80}{metricsPath}"))
+                    .AddManualStep(2, "Check endpoint", $"curl http://localhost:{metricsPort ?? 80}{metricsPath}")
+                    .WithRunbookUrl("docs/doctor/articles/observability/observability-metrics.md"))
                 .WithVerification("stella doctor --check check.observability.metrics")
                 .Build();
         }

src/__Libraries/StellaOps.Doctor.Plugins.Observability/Checks/OpenTelemetryCheck.cs

@@ -125,7 +125,8 @@ public sealed class OpenTelemetryCheck : IDoctorCheck
                 .WithCauses(issues.ToArray())
                 .WithRemediation(r => r
                     .AddManualStep(1, "Set service name", "Configure OTEL_SERVICE_NAME environment variable")
-                    .AddManualStep(2, "Verify endpoint", "Ensure OpenTelemetry collector is running"))
+                    .AddManualStep(2, "Verify endpoint", "Ensure OpenTelemetry collector is running")
+                    .WithRunbookUrl("docs/doctor/articles/observability/observability-otel.md"))
                 .WithVerification("stella doctor --check check.observability.otel")
                 .Build();
         }

src/__Libraries/StellaOps.Doctor.Plugins.Observability/Checks/TracingConfigurationCheck.cs

@@ -116,7 +116,8 @@ public sealed class TracingConfigurationCheck : IDoctorCheck
                 .WithCauses(issues.ToArray())
                 .WithRemediation(r => r
                     .AddManualStep(1, "Set sampling ratio", "Configure Tracing:SamplingRatio between 0.01 and 1.0")
-                    .AddManualStep(2, "Enable instrumentation", "Enable HTTP and database instrumentation"))
+                    .AddManualStep(2, "Enable instrumentation", "Enable HTTP and database instrumentation")
+                    .WithRunbookUrl("docs/doctor/articles/observability/observability-tracing.md"))
                 .WithVerification("stella doctor --check check.observability.tracing")
                 .Build());
         }