Relayer wallet low balance alert via Telegram

[Huygon764]

Problem: The relayer wallet can run out of gas at any time without the team being aware (as happened previously on Base). There is no monitoring or notification mechanism to warn when the balance is low, causing transactions to fail silently.

Expected behavior: A NestJS cron job runs daily at 6:00 AM (UTC+7), checks the relayer wallet balance on Horizen and Base. If balance falls below threshold (Horizen: 0.0001 ETH, Base: 0.0005 ETH), sends an alert via Telegram bot with chain name, current balance, and threshold. Retries up to 3 times with exponential backoff (2s → 4s → 8s) on Telegram API failure. No message sent if balances are healthy.