Add demo workflow for meda VM SSH system info collection

[Copilot]

This PR adds a new GitHub Actions workflow that demonstrates how to use meda to create VMs and collect system information via SSH in CI/CD pipelines.

What's Added

The new .github/workflows/demo-meda-usage.yml workflow showcases a complete meda VM lifecycle:

1. VM Management: Creates and starts a VM named "demo-vm"
2. IP Discovery: Uses meda ip demo-vm --json to retrieve the VM's IP address
3. SSH Connectivity: Establishes SSH connection using sshpass with username/password 'cirun'
4. System Info Collection: Runs essential system diagnostic commands:
   • df -h - Disk usage information
   • free -h - Memory usage information
   • uname -a - Operating system and kernel information
   • lscpu - CPU information

Key Features

• Robust Error Handling: Implements retry logic for VM IP availability and SSH connectivity
• Clear Output Formatting: Uses emojis and separators to make workflow logs easily readable
• Automatic Cleanup: Ensures VMs are properly stopped and deleted after execution
• Debug Support: Provides detailed debugging information on workflow failures
• Best Practices: Follows existing workflow patterns with proper timeouts and caching

Use Case

This workflow serves as a practical example for developers who want to:

• Integrate meda VM management into their CI/CD pipelines
• Collect system metrics from managed VMs
• Automate VM provisioning and system monitoring tasks
• Use SSH automation with meda-managed virtual machines

The workflow runs on push/PR to main branch and can also be triggered manually via workflow_dispatch.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• httpbin.org
  • Triggering command: /home/REDACTED/work/meda/meda/target/debug/deps/meda-e7afea13faa48d0d --quiet (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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