DoS protection

[AlyaGomaa]

dds a DoSProtector class that:

• Monitors input throughput (flows per minute) and activates when it exceeds a defined threshold (2000 flows/min).
• Applies adaptive sampling using a quadratic formula (flows² / 20000) to determine how many flows to skip.
• Runs sampling in time windows (60s), periodically re-evaluating traffic to decide whether to continue or stop.
• Adds CLI logging when sampling starts, extends, or stops.