fix: correct Mermaid graph syntax for endpoint labels with slashes

Mermaid graphs require node labels with special characters like forward
slashes to be quoted. Changed /healthz and /metrics from square bracket
format to quoted string format to fix the lexical error.

docs/content/architecture/module-integration-patterns.md

@@ -247,11 +247,7 @@ sequenceDiagram
     participant AuthzService
     
     Module->>ModuleManifest: Define permissions
-    ModuleManifest->>ModuleManifest: permissions:
-      - blog.post.create
-      - blog.post.read
-      - blog.post.update
-      - blog.post.delete
+    ModuleManifest->>ModuleManifest: permissions: blog.post.create, blog.post.read, blog.post.update, blog.post.delete
     
     Module->>PermissionGenerator: Generate permission code
     PermissionGenerator->>PermissionGenerator: Parse manifest

docs/content/architecture/system-behavior.md

@@ -327,7 +327,7 @@ Health checks and metrics provide visibility into system health and performance.
 
 ```mermaid
 graph TD
-    HealthEndpoint[/healthz] --> HealthRegistry[Health Registry]
+    HealthEndpoint["/healthz"] --> HealthRegistry[Health Registry]
     HealthRegistry --> CheckDB[Check Database]
     HealthRegistry --> CheckCache[Check Cache]
     HealthRegistry --> CheckEventBus[Check Event Bus]
@@ -339,7 +339,7 @@ graph TD
     Aggregate -->|All Healthy| Response200[200 OK]
     Aggregate -->|Unhealthy| Response503[503 Service Unavailable]
     
-    MetricsEndpoint[/metrics] --> MetricsRegistry[Metrics Registry]
+    MetricsEndpoint["/metrics"] --> MetricsRegistry[Metrics Registry]
     MetricsRegistry --> Prometheus[Prometheus Format]
     Prometheus --> ResponseMetrics[Metrics Response]