Parser: { f = e; f = e; ... } -> (:record (F E)...). { base with f = e;
... } -> (:record-update BASE (F E)...). Eval builds a dict from field
bindings; record-update merges the new fields over the base dict — the
same dict representation already used for modules.
{ also added to at-app-start? so records are valid arg atoms. Field
access via the existing :field postfix unifies record/module access.
Record patterns deferred to a later iteration.
giles
7fb65cd26a