Fix: web/REST memory-type write path

You can now set a Memory to any of the six types (Decision, How-to, Standard, Fact, Event, Note) from the edit drawer, and a type you choose by hand sticks — the classifier won't overwrite it. Previously, editing a Memory's type to How-to, Standard, Event, or Note was silently ignored because the REST handler still checked a legacy four-type list. Creating a Memory with an explicit type now also marks it as a human override so automatic reclassification leaves it alone.