How do you implement retry policies and resilience?

Resilience protects APIs from transient failures and cascading outages:

• Use Polly for retry, circuit breaker, timeout, fallback, and bulkhead isolation policies.
• Retry only for safe operations (idempotent GET or PUT).
• Use exponential backoff and jitter to avoid retry storms.
• Wrap external API calls, DB operations, and messaging clients with policies.
• Monitor policy behavior to detect fragile dependencies.