VM cannot connect via HTTPS due to self-signed certificate errors.
Added:
- test-vm-connectivity.ps1: 5-step diagnostic for VM
- agent/QUICK-FIX-VM.md: Use HTTP for Hyper-V local network
- open-firewall-for-vm.ps1: Open Windows Firewall
Since VM and host are on same physical machine (Hyper-V internal
network), HTTP is acceptable for local monitoring.
For production: Use proper TLS certificates.
