## Summary
Add circuit breaker support for AI Bridge to protect against cascading
failures from upstream AI provider rate limits (HTTP 429, 503, and
Anthropic's 529 overloaded responses).
## Changes
- Add 5 new CLI options for circuit breaker configuration:
- `--aibridge-circuit-breaker-enabled` (default: false)
- `--aibridge-circuit-breaker-failure-threshold` (default: 5)
- `--aibridge-circuit-breaker-interval` (default: 10s)
- `--aibridge-circuit-breaker-timeout` (default: 30s)
- `--aibridge-circuit-breaker-max-requests` (default: 3)
- Update aibridge dependency to include circuit breaker support
- Add tests for pool creation with circuit breaker providers
## Notes
- Circuit breaker is **disabled by default** for backward compatibility
- When enabled, applies to both OpenAI and Anthropic providers
- Uses sony/gobreaker internally via the aibridge library
## Testing
```
make test RUN=TestPoolWithCircuitBreakerProviders
```