Let users toggles MCPs as easily as it's with skills.

### Describe the feature or problem you'd like to solve

MCP toggling requires explicit commands, skills can be toggled from the list with spacebar/enter.

### Proposed solution

As it is already with skills users should be ready to type /mcp, move up and down the list and toggle them on/off with the space bar/enter.
MCPs take lots of context and it should be easy to toggle them on/poff without requiring individual commands.

### Example prompts or workflows

_No response_

### Additional context

_No response_

Start with the existing skills list interaction and the /mcp command flow described in the issue. Add equivalent list navigation and spacebar/Enter toggling for MCPs, then verify that users can enable and disable MCPs without individual commands.

Written by the indexing model from the issue text.