prototype-to-product

Hardens a working prototype into a pre-release product. Keeps a HARDENING.md gap ledger (release bar plus the itemized open gaps), loaded at session start together with the hardening standing rules, plus a non-blocking reminder to keep the ledger current. Ships assess-prototype (build the ledger), define-release-target (set the bar and prioritize, extending SPEC.md if present), and convert-prototype (work the ledger down one item per commit). Activates only once a HARDENING.md exists.