Document a database schema

Write developer-facing documentation for the following database schema: [Paste the schema SQL or ER description]. For every table: provide a plain-English description of its purpose and the domain entity it represents, document each column with its data type, constraints, nullable status, and a description of what it stores, explain all foreign key relationships and what they mean in business terms, list important indexes and explain what query patterns they optimise, and describe the primary read and write access patterns the application uses against this table.