fix: harden wallet balances and service startup

src/presentation/dependencies/commands.py

@@ -1,3 +1,4 @@
+from functools import lru_cache
 from fastapi import Depends
 from src.application.abstractions import IUnitOfWork
 from src.application.commands import (
@@ -54,13 +55,18 @@ def get_list_organization_wallets_command(
     return ListOrganizationWalletsCommand(unit_of_work=unit_of_work, logger=logger)
 
 
+@lru_cache(maxsize=1)
+def _wallet_balance_service() -> WalletBalanceService:
+    return WalletBalanceService()
+
+
 def get_get_organization_wallet_balances_command(
     logger: ILogger = Depends(get_logger),
     unit_of_work: IUnitOfWork = Depends(get_unit_of_work),
 ) -> GetOrganizationWalletBalancesCommand:
     return GetOrganizationWalletBalancesCommand(
         unit_of_work=unit_of_work,
-        balance_service=WalletBalanceService(),
+        balance_service=_wallet_balance_service(),
         logger=logger,
     )