[router] add reasoning parser base structure (#9310)

Co-authored-by: Chang Su <chang.s.su@oracle.com>

sgl-router/src/lib.rs

@@ -7,6 +7,7 @@ pub mod metrics;
 pub mod middleware;
 pub mod openai_api_types;
 pub mod policies;
+pub mod reasoning_parser;
 pub mod routers;
 pub mod server;
 pub mod service_discovery;