fix: improve vagrant-qemu configuration for Apple Silicon

[NormB]

Summary

• Configured unique SSH ports per VM (52222-52224) to avoid port collisions
• Set up HVF acceleration with recommended Apple Silicon settings
• Use generic/debian12 ARM64 box (properly downloads as arm64 architecture)
• Increased boot timeout to 1200s for slower first boots
• Documented known issues with SSH timeouts during boot
• Added alternative virtualization approaches (VirtualBox 7.1+, UTM, Lima)

Problem

vagrant-qemu was failing to boot VMs due to:

1. SSH port collisions when starting multiple VMs
2. Incompatible CPU model configuration
3. Boot timeouts during initial VM provisioning

Test plan

• Vagrantfile syntax validation
• Full VM boot test (requires longer timeout)
• SSH connectivity test

Notes

The vagrant-qemu setup on Apple Silicon has known challenges with certain box images. Alternative approaches documented in README if issues persist.