Smart Contract Event Listener for Claim Adjudication

[Olowodarey]

When our Soroban smart contract updates the status of a medical claim directly on-chain, our off-chain database needs to stay synchronized.

Acceptance Criteria

• Implement a long-polling or subscription service interfacing with Stellar Horizon.
• Filter events specifically for our deployed Smart Contract IDs.
• When an AdjudicationComplete equivalent event is emitted, update the corresponding MedicalClaim status in PostgreSQL.
• Ensure idempotency (we don't process the same event twice if the service restarts).