[router] Move all protocols to spec.rs file (#9519)

sgl-router/src/server.rs

@@ -1,10 +1,7 @@
 use crate::config::RouterConfig;
 use crate::logging::{self, LoggingConfig};
 use crate::metrics::{self, PrometheusConfig};
-use crate::protocols::{
-    generate::GenerateRequest,
-    openai::{chat::ChatCompletionRequest, completions::CompletionRequest},
-};
+use crate::protocols::spec::{ChatCompletionRequest, CompletionRequest, GenerateRequest};
 use crate::routers::{RouterFactory, RouterTrait};
 use crate::service_discovery::{start_service_discovery, ServiceDiscoveryConfig};
 use axum::{