Use when the active specflo project is at harden level (`specflo status` shows the harden level), or the user asks to harden code that already exists through specflo ("harden this module", "shake the bugs out of X", "review and fix it until it is clean"). Works one brief that names the scope, runs fresh-context harden rounds whose findings become fix tasks, and stops on the user's say. Do NOT use for new work (use specflo-quick or the phase skills), or for the review at the end of a normal project (that is the specflo-execute skill).
