Add a 'lab show/describe' command to re-display a lab's task without re-applying it

right now there is no way to show a lab's task again without re-applying the broken scenario.

`lab run ` prints the task, but once it scrolls away the only options are running `run` again (which re-applies the break) or `lab solution` (which spoils the answer).

for a practice tool it would help to re-read the prompt while still working on the lab.

happy to help with this if useful.

Start by locating the existing lab run and solution command entry points in this Go CLI and reviewing how they retrieve and display a lab task. Add a show or describe path that re-displays the task without re-applying the scenario or revealing the solution; done means the prompt can be viewed again safely while working.

Written by the indexing model from the issue text.