Wow! That would be incredible! I don't have the agents control the browsers like you are doing. I'm watching to see what you do though because that is incredible. The performance hit is real though -- I may look at libghostty.

I went the similar path of going vertical tabs after having worked that way in iTerm2 for months. Here's what I currently have:

Project-based organization -- Group sessions by working directory with a visual icon strip sidebar.

Multiple session types -- Claude Code sessions, standalone terminal shells, and embedded browser tabs.

Session persistence -- Terminal output is logged and replayed on relaunch so you never lose context.

Session resume -- Claude Code sessions detect their session ID automatically and resume where you left off.

Planning mode -- Draft and refine plans in a built-in text editor, then send them to Claude with one click.

Planning templates -- Start plans from structured templates for bug reports, feature requests, code reviews, refactors, and more.

Auto-titling -- Generic session names are replaced with descriptive titles generated by Claude after the first exchange.

Theming -- Light and dark themes with full CSS variable control.

Native menus and keyboard shortcuts -- macOS-native menu bar with comprehensive shortcut coverage.

Resizable layout -- Adjustable sessions sidebar width with state persistence across restarts.

Dock badge -- macOS dock icon shows the number of actively working Claude sessions.

Pin and archive -- Pin important sessions to the top or archive completed ones to keep the list clean.

Session card view -- See all sessions in a sortable grid with activity stats, token counts, and quick actions.

File tracker -- See which files Claude creates, modifies, and deletes in a live sidebar panel.

Macros -- One-click buttons for frequently used commands like /clear or commit this work.

Remote mode -- Monitor and control sessions from your phone via an encrypted WebSocket relay.

It has become my development hub where I can iterate very quickly.