- form extensions: placement across three plugins, required plugins' tabs
and fields, Hide with neighbours and whole tabs, spans, grouping only of
extended forms; every remaining boot error with plugin, controller and
offending name
- record events: the pure snapshot/diff (create, update, pointers, times as
instants, timestamps and key omitted, per-locale translations) and the
value helpers
- descriptors: MatchPattern edge cases, MatchPath ordering, types without
Content, duplicate Model/Controller across plugins
- ContentType, ContentTypeForController, Records and MatchPath on the
registry; the pure MatchPattern for whole-segment placeholder matching
- two types declaring the same Content.Model or Controller stop the boot
- TestContent* cover lookups, optional Records, boot errors, MatchPattern
and MatchPath precedence (first exact, else first inexact)
- docs: Content descriptors in menu-item-types.md, signpost README
