Add tsk namespace tasks for the full namespace task listing
Complement to tsk list (which only shows the active queue): walks the
namespace's id mapping and prints every (human id, title) bound there,
including dropped tasks. Defaults to the active namespace; an optional
positional name targets a specific one.
Tests: workspace test confirms dropped tasks remain visible since
their namespace binding is preserved.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>