Close feature

Pass the selected authorized feature root explicitly; omission is safe only from its registered feature worktree. Input mode is ready (default), pr, or merge.

Closeout

1. Close the implementation workstream when all required children are complete:

   "{baseDir}/../../bin/dstack" ctl feature finish-workstream [feature]
   "{baseDir}/../../bin/dstack" ctl feature claim-closeout [feature]
   "{baseDir}/../../bin/dstack" ctl feature scaffold-reconciliation [feature]