[Copilot CLI][Code agent] support reportProgress when running long time task

[zhoufenqin]

Describe the feature or problem you'd like to solve

report progress or send notification when running a long time task

Proposed solution

our mcp tool is used to assess a project and sometimes it may take long time.
in VSCode, we will use reportProgress feature to report the progress

then it can show the progress in mcp tool

But Copilot CLI or coding agent can't show the progress, it will make use lose patience. Hope the reportProgress can be provided

Example prompts or workflows

No response

Additional context

No response