added constant drift incrementing for tcc, tif values

app/models/solver_run.py

@@ -1,5 +1,5 @@
 from pydantic import BaseModel
-from typing import List, Optional
+from typing import List, Literal, Optional
 
 import logging
 
@@ -20,6 +20,7 @@ class SolverRun(BaseModel):
     total_form_items: int
     total_forms: int = 1
     theta_cut_score: float = 0.00
+    drift_style: Literal['constant', 'variable'] = 'constant'
     advanced_options: Optional[AdvancedOptions]
     engine: str