fix: bugs-01

backend/app/services/matching_service.py

@@ -1,13 +1,14 @@
 """Transaction deduplication and matching engine.
 
-Multi-layer strategy:
-  1. Exact order_no match
-  2. Amount + time-window + account-tail match
-  3. Fuzzy text similarity (placeholder for LLM-assisted matching)
+Strategy:
+  1. Deduplicate only by exact order_no match
+  2. Mark transit (self-transfer) records for exclusion from fraud totals
+
+Note:
+  Highly similar records (same amount/time/counterparty) are preserved so they
+  can be reviewed by officers in the assessment review stage.
 """
 from uuid import UUID
-from datetime import timedelta
-
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.transaction import TransactionRecord