Feature request: don't leave every edited file open as a tab

## Feature request

Avoid opening every edited file as a persistent editor tab when the agent makes changes.

## Problem

After an editing-heavy agent run, VS Code can be left with a very large number of open tabs because each edited file gets opened.

This creates a lot of tab clutter and makes the workspace harder to use after the agent finishes.

## Requested behavior

Please add an option so that edited files do **not** all remain open as tabs.

Possible approaches:
- perform edits without opening persistent tabs where possible
- use preview editors instead of pinned tabs
- auto-close tabs opened only for agent-applied edits
- add a setting controlling this behavior

## Ideal outcome

The agent can still edit files normally, but the user is not left with dozens of open tabs after the run.

## Related but different

This is different from showing a list of modified files in the UI. There is already a separate request around surfacing edited-file lists near the input. This request is specifically about preventing tab explosion during agent edits.