Fault-tolerance primitives — retries, circuit breakers, timeouts, fallbacks, and health checks

Notes & tips

• Decorators are the common path; classes are for control. Reach for @retry / @circuit_breaker / @timeout first.
• Name your breakers. A stable name shares one breaker across call sites via get_circuit_breaker.
• Narrow retryable_exceptions. Don't retry bugs.
• Mind the async primitives. with_fallback / with_timeout return / take coroutines.