Feature — Circuit Breaker Service #20

As a developer,
I want a circuit breaker for broker calls,
So that repeated failures don’t overload the system or the external API.

Acceptance criteria

• AC1: A circuit breaker is implemented for each broker adapter.
• AC2: The circuit breaker opens (stops sending requests) after N consecutive failures.
• AC3: The circuit breaker moves to a half-open state after a configured timeout, allowing one test request.
• AC4: A successful test request closes the breaker; a failed one keeps it open.
• AC5: The state of the circuit breaker (OPEN, CLOSED, HALF-OPEN) is exposed via the /status endpoint.

Definition of Done

• Code implemented in a feature/fix branch
• Unit / integration tests added or existing tests updated
• Linting passed and code builds locally
• Docs / README updated if behavior changed
• PR opened and linked (Closes #<issue-number>)
• Manual QA steps verified (if applicable)