add new chat corrector

在助理最终执行物理SQL前，加入一步LLM优化性能功能

headless/api/src/main/java/com/tencent/supersonic/headless/api/pojo/SqlInfo.java

@@ -16,4 +16,7 @@ public class SqlInfo implements Serializable {
 
     // SQL to be executed finally
     private String querySQL;
+
+    // Physical SQL corrected by LLM for performance optimization
+    private String correctedQuerySQL;
 }

headless/api/src/main/java/com/tencent/supersonic/headless/api/pojo/enums/ChatWorkflowState.java

@@ -8,5 +8,6 @@ public enum ChatWorkflowState {
     VALIDATING,
     SQL_CORRECTING,
     PROCESSING,
+    PHYSICAL_SQL_CORRECTING,
     FINISHED
 }