[Feature Request]: Allow @mssql /connect in the Github Copilot CLI

### Feature Description

i would like to access the extension from the copilot cli
i can use `@mssql /connect` in the gui chat but not the cli chat.

### Problem and Motivation

trying to use 1 tool for everything

### Related Area

- [ ] Connection dialog (SQL Server | Azure browse/Fabric browse)
- [ ] Query editor
- [ ] Query results panel
- [ ] Object Explorer
- [x] GitHub Copilot integration
- [ ] Preview/Edit data
- [ ] Table Designer
- [ ] Schema Designer
- [ ] Schema Compare
- [ ] Local SQL Server Container provisioning
- [ ] SQL database in Fabric provisioning
- [ ] DACPAC/BACPAC export/import
- [ ] SQL Database projects
- [ ] Query Plan Visualizer
- [ ] Other (please describe below)

### If you selected "Other", please describe the area

_No response_

### Confirmation

- [x] I have searched existing feature requests and couldn't find a match
- [ ] I want to help implement this feature

No files or tests are named in the issue. Start by locating the GitHub Copilot integration and the handlers for @mssql /connect in the GUI and CLI chat paths; done means the command works from Copilot CLI as it does from GUI chat, with appropriate coverage added for the CLI path.

Written by the indexing model from the issue text.