error_codes: added NOT_BATON_HOLDER error code and helper

src/aare/common/error_codes.py

@@ -25,6 +25,7 @@ class AuthErrorCode(StrEnum):
     # Authorization
     NOT_STAFF = "NOT_STAFF"
     NOT_IN_ACTIVE_PGROUP = "NOT_IN_ACTIVE_PGROUP"
+    NOT_BATON_HOLDER = "NOT_BATON_HOLDER"
 
 
 class DAQErrorCode(StrEnum):
@@ -48,6 +49,8 @@ _ERROR_CODE_HELP: dict[str, str] = {
         "A different session currently owns control. Use “force current session” (if allowed) "
         "or wait for the active session to expire/end."
     ),
+    AuthErrorCode.NOT_BATON_HOLDER: (
+        "A different session currently owns the baton. Request the baton or wait for active session to expire/end"),
     # Authorization
     AuthErrorCode.FORBIDDEN: (
         "Generic permissions failure. The user is authenticated but not allowed to perform this action."