Improve WSL & Windows compatibility for SSH tunnels and editors

[oliverholworthy]

This PR enhances compatibility with Windows and Windows Subsystem for Linux (WSL) environments by addressing several issues:

SSH Tunneling Improvements

• Fix SSH tunnel configuration in WSL environments by properly managing both Windows and WSL SSH config files
• Update SSH tunnel naming to use a simpler format (removing devspace name duplication)
• Use proper path formatting with as_posix() in tunnel server code

Editor Support Enhancements

• Add robust editor detection that works correctly in Windows, Linux, and WSL environments
• Properly handle Windows executables from WSL for VS Code and Cursor editors
• Add detailed error messages to guide users through editor setup issues
• Ensure environment variables are set correctly for each platform

Testing & Dependencies

• Add tests for the editor detection functionality
• Add WSL-specific tests for the SSH config handling

This allows users on any platform to seamlessly use SSH tunnels and launch editors, particularly improving the experience for those using WSL.