> I want to have a fullblown cursor instance/window for each task I have, and a central Hub that manages spawning those instances, setting up the worktrees, etc.

I am working on exactly this interface for my new tool called Kotkit. You start with kanban board management of workspaces. Each workspace (worktree on one/multiple repos) is a feature-rich IDE interface in a remote-capable in-browser desktop. You can spawn multiple agents with a good UI wrapper and full auditable logs, solve worktree rebase/merge with 1-click AI features, and there is also an embedded VSCode to solve edge cases. It also supports very deep plugin integration like IntelliJ.

Currently dogfooding it on my own projects and will be released sometime soon.