Remove recipe and promotion from derived_metadata: unimplemented concepts

[jonathanrobie]

Background

derived_metadata.schema.json contains two fields from concepts that were never implemented:

recipe

recipe is currently required for derived burritos. It was designed for an "ecosystem servers" concept where a server would process a list of operations (each with idAuthority, operation, and data) to produce derived content. This concept was never built out.

Requiring recipe is too strict — a back-translation is a derived burrito but has no meaningful recipe from a server. The only example of a derived burrito (textTranslation_derived.json) includes a recipe with a single DBL apply_license_agreement step, which reflects the DBL ecosystem server design.

promotion

promotion provides localized plain and rich text for marketing/promotional purposes. It was designed for the now-removed print Bible flavors (typesetScripture, embossedBrailleScripture). Those flavors have been removed; promotion has no current use case.

Fix

• Remove recipe from the required array in derived_metadata.schema.json (keep as optional with a $comment)
• Remove promotion from derived_metadata.schema.json entirely

Impact

Removing recipe from required is a breaking change for validators. Removing promotion is a breaking change for any derived burrito that includes promotion data (no known examples exist).

[jonathanrobie]

Both fixes have been applied:

• recipe is no longer in the required array in derived_metadata.schema.json — it is retained as an optional field with a $comment explaining it is from an unimplemented ecosystem servers concept (kept for backwards compatibility).
• promotion has been removed from derived_metadata.schema.json.

The schema docs still include a generated page for recipe.schema.json since the schema file itself remains. The retention rationale is documented in the $comment in derived_metadata.schema.json.