Four things that share a spine, so they arrive together.
**Folders.** A hand-picked set of questions, and the fourth thing a grant can
name beside exam, discipline and category. Deliberately not `user_collections`
with a sharing flag: a library is a consequence of access — you save what you
can already see — while a folder is a source of it, and one table holding
thousands of private lists beside a handful that confer permission is one
mistake away from a leak. Built from the question manager, granted on /access.
Membership stays with the owner and moderators so a grantee cannot widen their
own reach, and deleting a folder takes its grants with it.
Two live constraints had to be rewritten to accept it: `ck_grant_has_a_dimension`
and `uq_grant_dimensions` both predate `folder_id`, so a folder-only grant
failed the check and two folder grants collided on the unique index.
**Per-question feedback.** The learner's half already existed. What was wrong
was who could read it: any grant at all let an educator list and delete reports
about the whole bank. Reports are now scoped by `question_scope_predicate`, the
same predicate that decides which questions that educator can see, and a reply
thread makes the report a conversation the learner can follow rather than a
form that swallows what they said.
**Per-section notes and article feedback.** Two tables on purpose:
`article_section_notes` is private to whoever wrote it, `article_feedback` goes
to whoever maintains the article. Both point at the section id inside
`articles.sections` rather than at `article_section_index`, whose rows are
dropped on unpublish — a cascade from there would delete a learner's writing
because an educator took an article down for an afternoon. A rename keeps a
note attached; a deleted section leaves it marked orphaned under the heading it
was written on, for its writer alone to remove.
The header's feedback badge covers both, because questions and reading are the
same job to whoever is doing it.
Migration i9f0a1b2c3d4. 556 backend and 572 frontend tests pass.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TqXevQJhxFrM7jJg82cgZN
