- Implement CircuitBreaker class with CLOSED/OPEN/HALF_OPEN states
- Configurable failure threshold, success threshold, and timeout
- Fallback behavior when circuit opens (returns neutral 0.5 score)
- State change callbacks for monitoring and logging
- Comprehensive metrics tracking (executions, failures, successes, timestamps)
- Update SpamShieldService to use circuit breakers for both Hiya and Truecaller
- Add parallel API calls with graceful degradation
- Export circuit breaker types and service interfaces
- 32 unit tests covering circuit transitions, fallback, and service integration
Co-Authored-By: Paperclip <noreply@paperclip.ing>
Michael Freno
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