Add Enable/Disable Toggle for MCP Server Configurations

Bug Description
"Add enable/disable toggle for MCP servers instead of requiring remove/add cycle"

Key points to include:

1. Current behavior: Only add/remove commands available
2. Problem: Removing loses all configuration (env vars, auth, parameters)
3. Impact: Must reconfigure everything to re-enable a server
4. Use cases:

• Temporary debugging
• Testing without certain integrations
• Development vs production workflows
• Resource management

Proposed solution:
claude mcp enable <server-name>
claude mcp disable <server-name>
# Or a toggle command
claude mcp toggle <server-name>

This would preserve all configuration while just controlling the server's active state.

Environment Info

• Platform: darwin
• Terminal: tmux
• Version: 1.0.80
• Feedback ID: