- Add fmt import and fix X-RateLimit-Limit header conversion from rune to string in ratelimit middleware
- Fix whitespace alignment for rate limiter variable declarations and JSON error responses
- Update mock expectations in redis_ratelimit_test to use explicit argument type matchers
- Add severity validation check in alerting_test rule validation
- Fix health_test assertions for degraded/unhealthy counts
- Add RedisClientInterface with Eval/Del/ZCount methods for Redis operation abstraction
- Update RedisRateLimiter/NewRedisRateLimiter/NewMultiTierRateLimiter to accept RedisClientInterface instead of concrete redis.Client
- Update MockRedisClient.Eval to properly construct call arguments with script and keys
- Update MockRedisClient.Del to accept keys as slice instead of variadic parameters