S4 — Count-pin land_gaul completeness + FAO disclosure of the 82 excluded cells (C-30)

[Polichinel]

Epic: #51 · risk-register C-30 (Tier 1) · depends on #53 (S2) · cross-repo deps below

Problem

At the global switch from africa_me_legacy to land/land_gaul, 82 sub-Antarctic cells (Macquarie, Auckland Islands, Prince Edward; sample gids 51078, 51798, 53979, 62356, 94776, 99027) have no GAUL assignment in any source. Through the lookup enricher they left-merge to NaN → _validate crashes — loud, but on delivery day. The register's chosen direction (D-10) excludes them upstream via a curated land_gaul region (land ∩ gaul0_code != -1, 64,736 cells), so they never arrive.

Context

• The enricher's left-merge + the _validate null-gate already make an unassigned cell crash rather than silently corrupt (good) — but the crash is unanticipated/undated; this pins it.
• land_gaul build is upstream (views-datafactory, D-10); the REGION flip is views-models#127.

Work (this-repo artifacts can be built now, against the known counts)

• Build on S2 — Coverage contract: assert expected cell count + log cell counts (C-34) #53's coverage assertion: count-pin land_gaul to 64,736 complete cells.
• Enumerate the 82 excluded gids as a named, count-asserted (== 82) constant + test — not a generic != -1 filter (which would silently absorb future coverage regressions).
• Produce the FAO disclosure content for the 82 excluded sub-Antarctic cells (for the release note).
• Verify (fixture now; live land_gaul dry-run when available) that enrichment yields 0 unmapped, and an injected unassigned cell still crashes loud.

Acceptance criteria

• A land_gaul fixture/run asserts exactly 64,736 complete + 82 named exclusions; counts pinned in a test.
• The 82 gids live in a constant + are documented for FAO disclosure.
• An injected unassigned/extra cell raises loud (no silent pass).

Dependencies

• views-datafactory: land_gaul curated region (D-10).
• views-models#127: flip REGION to land_gaul (gates the live run; the constant/test/disclosure can land first).
• S2 — Coverage contract: assert expected cell count + log cell counts (C-34) #53 (S2): the expected-count assertion mechanism.

Files

views_postprocessing/unfao/ (the exclusion constant + coverage pin), tests/, a disclosure note (docs or release-note snippet).