feat: add configurable retention period for Redis usage queue

- Introduced `redis-usage-queue-retention-seconds` config parameter with a default of 60 seconds and a max of 3600 seconds.
- Updated logic in `redisqueue` to honor configurable retention periods for enqueued usage data.
- Modified config validation and initialization to support and enforce retention limits.
- Enhanced change tracking in `config_diff` to detect updates to this parameter.

internal/api/server.go

@@ -1000,6 +1000,10 @@ func (s *Server) UpdateClients(cfg *config.Config) {
 		redisqueue.SetUsageStatisticsEnabled(cfg.UsageStatisticsEnabled)
 	}
 
+	if oldCfg == nil || oldCfg.RedisUsageQueueRetentionSeconds != cfg.RedisUsageQueueRetentionSeconds {
+		redisqueue.SetRetentionSeconds(cfg.RedisUsageQueueRetentionSeconds)
+	}
+
 	if s.requestLogger != nil && (oldCfg == nil || oldCfg.ErrorLogsMaxFiles != cfg.ErrorLogsMaxFiles) {
 		if setter, ok := s.requestLogger.(interface{ SetErrorLogsMaxFiles(int) }); ok {
 			setter.SetErrorLogsMaxFiles(cfg.ErrorLogsMaxFiles)