Attached documents: user guide + two developer pages (discussion #76)
Attached-Documents
what it does, in plain terms: a file OR a link, one document on several
records, who can see it, finding things, and the maintenance job
Attached-Documents-Developer-Guide
the colour-keyed file tables, the schema and the one decision that shaped it
(the parent is a ROW), adding a module, extraction's two tiers, orphan
collection, and the things that will bite
Attached-Documents-Permissions-and-Search
the rule and its consequences: why there is no permissions table, the two
shapes of the same question, where the check happens, why attaching is itself
a permission operation, why ⌘K asks twice, scale, the file on disk, and what
the tests actually cover
Split into two developer pages because it is a large feature and permissions is
the half somebody will come back to on its own.
Sidebar entry under Searching inside tickets, which is where the extraction
pipeline this borrows from already lives.