[FEATURE] Setting to opt out of markdown rendering for my own prompts

Problem Statement

Since 2.1.234 the TUI re-renders my message as markdown when it echoes it back, and there's no way to turn it off.

I don't see what this buys. I already know what I typed — rendering it tells me nothing new. All it does is make the transcript show something other than what I sent: backticks vanish, lists reflow, indentation appears that I never typed.

Nothing hints this will happen, either. The composer looks like a plain text field.

Proposed Solution

Option A: revert 2.1.234 and go back to echoing prompts as typed. That was the behavior for the tool's whole history before that release, no open or closed issue ever asked for the change, and it has already produced one meaning-changing regression (#92855).

Option B: a settings.json boolean, defaulting to current behavior.

{ "renderUserPromptsAsMarkdown": false }