feat(core): add inline-tui view mode [wip]

[AgentEnder]

[!IMPORTANT] This PR still represents work in progress. Things like interactivity, resizing many need work. The code is still somewhat messy. It likely does more than it should, and does things in the wrong place in the wrong way. Yes, AI was used pretty heavily. Yes, I still have some understanding of it. We'll clean it up before merging.

Current Behavior

When running single tasks we have a "minimal" tui, but that minimal tui still makes it really hard / impossible to use some of the terminals built in features... like:

• Find (can only find what's currently rendered by tui)
• Text select + copy (can only select what's rendered to screen, copied text includes the frame around the tui / scrollbar)

Expected Behavior

When running single tasks we can use an inline viewport to render some tui widgets at the bottom of the viewport, and terminal output can be printed above.

Related Issue(s)

Fixes #