fix: Lint fixes of core, models and schemas

app/models/credit_transaction.py

@@ -17,7 +17,8 @@ class CreditTransaction(BaseModel, table=True):
 
     user_id: int = Field(foreign_key="user.id", nullable=False)
     action_type: str = Field(nullable=False)
-    amount: int = Field(nullable=False)  # Negative for deductions, positive for additions
+    # Negative for deductions, positive for additions
+    amount: int = Field(nullable=False)
     balance_before: int = Field(nullable=False)
     balance_after: int = Field(nullable=False)
     description: str = Field(nullable=False)

app/models/extraction.py

@@ -25,7 +25,8 @@ class Extraction(BaseModel, table=True):
     status: str = Field(nullable=False, default="pending")
     error: str | None = Field(default=None)
 
-    # constraints - only enforce uniqueness when both service and service_id are not null
+    # constraints - only enforce uniqueness when both service and service_id
+    # are not null
     __table_args__ = ()
 
     # relationships