[Feature Request]: Autocomplete stored procedure parameters when completing procedure names

### Feature Description

When completing a stored procedure name in the SQL editor, automatically insert the procedure parameters along with the procedure name.

For example, after typing part of a procedure name and accepting completion for something like `sys.sp_addrole`, the editor should insert the procedure call template including parameter names and placeholders/defaults where possible.

This request is based on the Azure Data Studio issue https://github.com/microsoft/azuredatastudio/issues/8295.

### Problem and Motivation

Right now, completing a stored procedure only inserts the procedure name. The user then has to manually discover and type the parameter list.

That slows down a common workflow for calling procedures, especially system procedures or procedures with multiple parameters. It would be more useful if completion expanded into an executable template, for example:

`EXEC sys.sp_addrole @rolename = NULL, @ownername = NULL`

or similar parameter placeholders/snippets that allow fast tabbing through arguments.

This would:
- reduce the need to look up procedure signatures
- speed up authoring of `EXEC` statements
- make stored procedure completion more useful than simple name insertion

### Related Area

- Query editor
- Language service / IntelliSense behavior