[router] refactor router and worker management 3/n (#10727)

sgl-router/src/core/worker_registry.rs

@@ -34,7 +34,6 @@ impl Default for WorkerId {
     }
 }
 
-/// Type alias for the model index to reduce complexity
 type ModelIndex = Arc<DashMap<String, Arc<RwLock<Vec<Arc<dyn Worker>>>>>>;
 
 /// Worker registry with model-based indexing
@@ -54,8 +53,7 @@ pub struct WorkerRegistry {
 
     /// Workers indexed by connection mode
     connection_workers: Arc<DashMap<ConnectionMode, Vec<WorkerId>>>,
-
-    /// URL to worker ID mapping (for backward compatibility)
+    /// URL to worker ID mapping
     url_to_id: Arc<DashMap<String, WorkerId>>,
 }