CookIT/docs/adr/0003-units-are-data.md

Units are data: built-in ones plus the cook's own

Units used to be a fixed list in code. The cook wants to add their own (e.g. "Würfel"), choose which ones the picker offers directly and in what order, so units now live in a units table (schema version 2). The 27 built-in units are seeded from the Unit enum and keep their keys and localized names; the cook's own units get an own-<uuid> key and a stored name. Ingredient Lines keep storing just the unit's key, so existing recipes and version 1 Recipe Bundles stay valid.

Consequences

• Recipe Bundles are version 2: they carry the cook's own units (units), and an import creates the ones that are missing. Version 1 bundles (the Excel converter's) still import.
• Built-in units cannot be renamed or deleted: their keys are shared by every bundle and by the Excel converter.
• Deleting an own unit rewrites the Ingredient Lines that used it ("2 Würfel Brühe": the name moves into the ingredient), so no recipe points at a unit that no longer exists.