Module entity 

Manifest key-attribute derivation shared by the put / transaction write paths — a port of the _add_key_attributes / _fill / _fillable helpers.

Given an entity’s resolved item fields (a (name, value) list in insertion order), derive PK / SK and each fillable <index>PK / <index>SK from the manifest templates. pkTemplate is self-contained (segment key model), so no entity prefix is prepended.

Functions

add_key_attributes

Append PK / SK / GSI key attributes to item (in place), derived from the entity’s manifest key + GSI templates. A GSI key is only added when all its placeholders are fillable (parity with _add_key_attributes).