docs(study): preserve social source and image rules
docs(study): preserve review and recovery principles
docs: refer curriculum review status to issue handoff
docs: define elementary curriculum review criteria
docs: record study material and merge proof decisions
docs(study): distinguish practice volume from question-type coverage
docs: correct Traditional Chinese wording
docs: record faithful science choice and source identity rules
docs(study): retain partial source review decisions
docs(study): document unit-sharded catalog decisions
docs: record social diagram and source-version checks
docs(study): record social bank and curriculum mapping rules
docs(study): record historical angle image transfer rules
docs(study): record text batch delivery and source preservation
docs(study): record CDN verification order
docs(study): record 256 KiB pack capacity decision