Is your feature request related to a problem? Please describe.
There is no way to temporarily disable a configured MCP server without destroying its configuration. A user needs to delete it from the MCP config JSON (losing the command, args, and environment settings)

Describe the solution you'd like
A per-server enable/disable toggle on the MCP preference page. When a server is disabled: its configuration is preserved and Copilot Language Server does not start or connect to it. Re-enabling it restores full functionality in a single action.

Describe alternatives you've considered
Unchecking all tools under the server: The server process still starts and connects every session. Re-enabling requires rechecking each tool individually and there is no memory of which tools were previously enabled.

Additional context
N/A