Document and Remove Obsolete Worktree Limitations

Itemize limitations such as Pool Max, number of worktress, etc. Since all projects now use one-off / dynamic worktrees they are no longer relevant. Once itemized, present to the user and delete when approved. There is one feature: static slots/worktrees, that needs to be put behind an default/plan/org feature flag, off by default. This is preserved as a potential special case when a client is running a system so enormous that dynamic allocation is difficult.