Makes docs/AGENTS.md section structure the single source of truth for the
primary-vs-advanced agent classification and fails when docs/INVENTORY.md's
"Primary doc" column or the AGENTS.md prose counts drift from it.
The classification ("primary" = full role card, "advanced stub" = concise
stub) was hand-duplicated across three doc surfaces with no enforcement.
This drift guard derives the expected class from AGENTS.md section placement
and cross-checks the INVENTORY.md column, the prose counts, the parenthetical
advanced-agent list, and full roster completeness (21 primary / 12 advanced
/ 0 inventory-only today).
No agent frontmatter field is added (avoids the capability-registry `tier`
collision and the research-profiles.cjs ripple); the classification stays
documentary, enforced from where it is defined.
Closes#1171
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
