feat(auth): track unique tools in access metrics

* Add tool tracking to AccessTracker and metrics
* Update tests to validate tool tracking functionality
* Modify middleware to record tool usage
* Enhance observability with tool context
* Update UI to display unique tools in metrics

internal/observability/http.go

@@ -106,6 +106,11 @@ func RequestIDFromContext(ctx context.Context) string {
 	return value
 }
 
+func MCPToolFromContext(ctx context.Context) string {
+	value, _ := ctx.Value(mcpToolContextKey).(string)
+	return strings.TrimSpace(value)
+}
+
 type statusRecorder struct {
 	http.ResponseWriter
 	status int