fix: bugs-04

backend/app/services/matching_service.py

@@ -15,7 +15,7 @@ from app.models.transaction import TransactionRecord
 from app.models.transaction_cluster import TransactionCluster
 from app.repositories.transaction_repo import TransactionRepository
 from app.rules.dedup_rules import is_duplicate_pair
-from app.rules.transit_rules import is_self_transfer
+from app.rules.transit_rules import is_self_transfer, is_fee_tolerant_transit_pair
 
 
 async def run_matching(case_id: UUID, self_accounts: list[str], db: AsyncSession) -> None:
@@ -70,6 +70,15 @@ async def run_matching(case_id: UUID, self_accounts: list[str], db: AsyncSession
         if is_self_transfer(tx, self_accounts):
             tx.is_transit = True
 
+    # Rule extension: if an in/out pair occurs within 2 minutes and
+    # amount difference is within 2% (e.g. fee), mark both as transit.
+    non_duplicate = [tx for tx in transactions if not tx.is_duplicate]
+    for i, tx_a in enumerate(non_duplicate):
+        for tx_b in non_duplicate[i + 1 :]:
+            if is_fee_tolerant_transit_pair(tx_a, tx_b):
+                tx_a.is_transit = True
+                tx_b.is_transit = True
+
     await db.flush()