feat: add subscription and transaction repositories

- Implemented SubscriptionRepository with methods to get, create, and update subscriptions.
- Added BalanceTXRepository for creating and retrieving balance transactions.
- Introduced a test script for simulating Pally webhook for local testing.

repositories/transactions.py

@@ -0,0 +1,41 @@
+from datetime import datetime, timezone
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from db.models.transactions import BalanceTransaction, BalanceTxType
+
+
+class BalanceTXRepository:
+    async def create(
+        self,
+        session: AsyncSession,
+        user_id: int,
+        amount: int,
+        tx_type: BalanceTxType,
+        balance_before: int,
+        balance_after: int,
+        description: str,
+    ) -> BalanceTransaction:
+        created_at = datetime.now(timezone.UTC)
+        tx = BalanceTransaction(
+            user_id=user_id,
+            amount=amount,
+            tx_type=tx_type,
+            balance_before=balance_before,
+            balance_after=balance_after,
+            description=description,
+            created_at=created_at,
+        )
+        session.add(tx)
+        await session.commit()
+
+        return tx
+
+    async def get_transactions_by_id(
+        self, session: AsyncSession, user_id: int, limit: int = 50
+    ) -> list[BalanceTransaction]:
+        stmt = select(BalanceTransaction).where(BalanceTransaction.user_id == user_id).limit(limit)
+        res = await session.execute(stmt)
+
+        return list(res.scalars().all())