Portable deterministic audit receipt. Build completion now invokes the vendored Stelow helper's audit-trail build and audit-trail check after bb's checkout-bound audit.md gate. The generated receipt is the same cross-host contract, not a plugin-specific audit format.
Changed
Vendored Stelow core refreshed to 0.59.5-alpha. Includes deterministic audit-trail evidence hashes, mandatory final-audit generation, and removal of retired host-integration residue.