Vscode-style sticky-scrolling but with prompts

# Description of the new feature/enhancement

Original idea by [@lunasorcery](https://twitter.com/lunasorcery), approved by @DHowett
https://twitter.com/DHowett/status/1619856783119626242
You know how vscode is able to "stick" the namespace/class name or function signature to the top of the screen when some part of the relevant code scope is "above" the viewport? That, but for commands that output a bunch of data, with the original prompt/command being sticky.
This should increase the productivity in exactly the same manner as the feature does inside vscode: easier to browse large histories with commands outputting a bunch of stuff.
It could also be convenient to make the sticky part clickable to scroll up to the beginning of the command output.

# Proposed technical implementation details (optional)

No source file, entry point, or test is identified in the issue. Start by locating the terminal's command-output rendering and history display code, then review existing scrolling behavior. Done means command prompts remain visible while browsing multiline output and can optionally be clicked to return to that output's beginning.

Written by the indexing model from the issue text.