Official lists are versioned rules

Status: accepted · Date: 2026-11-06 · Related: ADR-0002, ADR-0015

Enforcement: scripts/leaf-modules.test.mjs (the // LEAF MODULE header), Brandt-household tests in packages/preparedness (82 L water, 67,000 kcal); packages/api/src/features/lists/lists.procedures.test.ts (seeded versions equal the package, publish needs two distinct sign-offs, published rows refuse UPDATE/DELETE/TRUNCATE through the list_version_immutable trigger and have no tenant UPDATE/DELETE grant).

Every quantity in Varu must cite its source, date and version, and a published version must never change (RNF12). The list is needed on the phone, in the web editor and in the API, and the phone must compute without a network.

Decision

A leaf, isomorphic package packages/preparedness. No I/O, no framework imports, a // LEAF MODULE header. It holds the list versions DE-2025.10 (BBK "Vorsorgen für Krisen und Katastrophen", 13.10.2025) and EU-72H (EU Preparedness Union Strategy, 26.03.2025), the quantity formulas and readiness. Mobile, web and API import it.
Formulas are rules, not code paths. Water 2 L/person/day; pets 0.2 L/pet/day (a hypothesis, marked as such); kcal/day adult 2,200, needs-help 1,900, child 1,500, baby 800; goal days 3, 7 or 10. Readiness is the mean of 8 areas; days is the minimum of water days and food days.
Published versions are immutable rows in Postgres for the editor and for GET /lists/:country/:version: a list version, its item rules, its source and two review sign-offs. Publishing inserts; nothing updates. A correction is a new version.
The app ships the versions it knows and learns newer ones from the API; the home records which version it follows.

Why not the alternatives

Rules only in Postgres. The phone would need the network to compute readiness, which breaks offline use.
Rules only in the app bundle. The municipality editor could not publish, and a correction would need a store release.

Consequences

Package and database must agree: a test loads each published seed version and compares it with the package.
Changing a formula is a new version, never an edit of DE-2025.10.