- rewrite every built-in as EventXxx implements BuiltInFunction<P, E>
(setBlock/moveBlock/deleteBlock/moveHero/moveHeroStep/touchFront/
insertEvents/insertEvent), matching the EventSetBlock reference style
- move shared helpers to event/utils.ts (getPossibleMap, getPossibleLayer,
getEventExecutor, enter/exitEventInsert); utils is not exported via index
- move per-class helpers into private methods (EventTouchFront and
EventInsertEvents collectInvocations)
- use IObjectMover.push for move sequences instead of manual step calls
- registrations.ts: one createEventRegistrations() writing the eight entries
in order, categories separated by single-line comments
- remove EventBuiltinName; classes own short string names
- update event tests; core.ts uses createEventRegistrations