fix(decision-logs): remove unused context_json + json import (ruff F841/F401)

backend/agenteval/intelligent_eval/decision_logs.py

@@ -3,7 +3,6 @@
 Pulled out of ``web/routers/intelligent_evals.py`` so the router only handles
 HTTP validation and error translation. The ORM writes and reads now live here.
 """
-import json
 from typing import Any
 
 from sqlmodel import Session, select
@@ -45,8 +44,6 @@ def create_decision_log(
     if eval_db is None:
         raise LookupError(f"intelligent eval {eval_id} not found")
 
-    context_json = json.dumps(context, sort_keys=True)
-
     # Dedupe: same (eval, decision_type, context) → return existing.
     for existing in session.exec(
         select(IntelligentEvalDecisionLogDB).where(