Adds internal/depot.Run, the stdlib-flag command surface for the five depot subcommands (0/1/2/64/70 exit contract), plus a dispatch special case that will route "crucible depot ..." and crucible-depot to it once Task 6 flips Wired:true (inert for now since Wired stays false). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>