SNMP device simulation for testing and development.

This module provides tools for creating and managing simulated SNMP devices:

• Start individual devices with custom profiles (start_device/2, linked to the caller)
• Create device populations for testing (start_device_population/2)
• Record a real device into a walk file (record/3)
• Send a trap from a simulated device (send_trap/4, to: names the receiver)

See SnmpKit.SnmpSim for configuration-driven start-up, listing and stopping devices, and docs/testing-guide.md for test patterns.