feat: add SendEnv SSH configuration support

[vitorpy]

Summary

Implements SendEnv directive parsing and environment variable forwarding to remote hosts, matching OpenSSH behavior.

Features

• Parse SendEnv directives from SSH config files
• Support wildcard patterns (e.g., LC_*, LANG)
• Filter and export local environment variables to remote
• Cross-platform support (Linux, macOS, Windows)
• Graceful degradation when remote doesn't accept env vars

Implementation Details

Files Modified

1. src/ssh/sshConfig.ts

   • Added 'sendenv': 'SendEnv' to SSH_CONFIG_PROPERTIES

2. src/authResolver.ts

   • Created globToRegex(): Converts glob patterns to regex
   • Created filterEnvBySendEnv(): Filters local env vars based on patterns
   • Extracts SendEnv config and filters process.env
   • Added comprehensive trace/info logging

3. src/serverSetup.ts

   • Updated ServerInstallOptions interface with sendEnvVars
   • Modified bash script generator to export env vars
   • Modified PowerShell script generator to set env vars

How It Works

1. Reads SendEnv directives from SSH config
2. Matches patterns against local environment variables with wildcard support (*, ?)
3. Exports matched env vars in the remote shell before starting VSCode server
4. Works on all platforms (Bash and PowerShell)

Example Usage

Host myserver
  HostName server.example.com
  SendEnv LANG LC_*
  SendEnv MY_CUSTOM_VAR

Testing

• TypeScript compilation successful
• Webpack bundling successful
• Manual testing with real SSH connection
• Verify environment variables on remote

Notes

• Assumes AcceptEnv is configured on the remote SSH server
• Handles both string and array formats from ssh-config library
• Includes debug logging for troubleshooting