VScode input box markdown should be optional

What version of the IDE extension are you using?

26.803.61601

What subscription do you have?

Corporate

Which IDE are you using?

VS Code

What platform is your computer?

Linux 6.18.33.2-microsoft-standard-WSL2 x86_64 x86_64 , Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

The input box has now become a wysiwyg markdown box.
Entering text here is being markdown rich text formatted as i type - this causes a lot of the frustration seen with rich text editing, where format characters are, what parts are in or not in. Pasting can be worse with unexpected markup occuring. Without being able to see the actual characters, this is then very awkward to edit.

What steps can reproduce the bug?

Typing or pasting with common markdown items.

What is the expected behavior?

The input box is plain text, an option to enable/disable the new behavior is present or code/preview selections are available.

Additional information

Related to - but not a duplicate of https://github.com/openai/codex/issues/32539. This relates to the whole typed and pasted input, not solely pasted input.

Reproduce the behavior in the VS Code extension by typing and pasting common Markdown into the input box. Trace the input-box implementation and determine how plain-text editing or a code/preview choice can be exposed; done means users can avoid forced Markdown formatting while typing and pasting.