Ahoy says the docs target defaults to skip, writing no conventions file; embark says no saved choice gives AGENTS.md

Ahoy says the docs target defaults to skip, writing no conventions file; embark says no saved choice gives AGENTS.md

A premise contradiction (severity minor) found by the cross-document consistency pass.

• End A: .abcd/development/brief/04-surfaces/03-embark.md:131 — "agents_md or no choice saved gives AGENTS.md"
• End B: .abcd/development/brief/04-surfaces/01-ahoy.md:1070 — "so the docs target defaults to skip: a default install writes it into none of the repository's committed conventions files"

Ahoy says the docs target defaults to skip, so a default install plants the marker block in none of the repository's conventions files and a project must name agents_md to get it. Embark reads docs.target with setup's reader yet maps no saved choice to AGENTS.md, so an embark into a target with no saved choice writes the block where a default install would write nothing. The two disagree on what the absent setting means.

Evidence: .abcd/work/reviews/2026-10-26-consistency/00-summary.md, finding 258.