Implement circuit breaker event indexing and current state API

[Chucks1093]

Summary

Index CircuitBreakerTripped events and expose an endpoint returning the circuit breaker configuration and recent trip history for each creator key.

Scope

• GET /keys/:keyId/circuit-breaker — config (max_bps), active flag, and trip history
• CircuitBreakerTripped events indexed with actual_bps and timestamp
• Trip history paginated, last 50 events returned by default
• Current max_bps config fetched from contract and cached 5 minutes
• Trip events trigger in-app notification for key creator

Acceptance Criteria

• Endpoint returns correct config and trip history
• CircuitBreakerTripped events indexed correctly from contract
• Trip history paginated correctly
• Config cache refreshed every 5 minutes
• Creator notification triggered on each trip event

ETA

12 hours

[Ranjeet2063]

Hello maintainers,

I would love to take on implementing the circuit breaker event indexing pipeline and state API. I have strong experience building robust TypeScript backend architectures and on-chain event indexers. My roadmap:

1. Event Indexer Handler: Subscribe to and parse CircuitBreakerTripped events, extracting actual_bps, timestamp, key identifier, and trigger conditions into the database with idempotent upsert guards.
2. REST Endpoint Implementation: Build GET /keys/:keyId/circuit-breaker returning current breaker configuration (max_bps), active status flag, and cursor-paginated trip history (default 50 records).
3. Validation & Error Handling: Enforce strict parameter validation, type-safe response schemas, and resilient database query optimization with proper indexing.
4. Unit & Integration Tests: Deliver comprehensive integration tests covering event ingestion, pagination boundaries, and empty history edge cases.

Ready to start right away and submit a clean PR adhering to all repo standards!