[common/hc] Add hh.emitter to typedefs

common/hellcooling/config/global.d.ts

@@ -1,7 +1,9 @@
 export {};
+import { EventEmitter } from 'events';
 
 declare global {
   const hh: {
+    emitter: EventEmitter;
     constants: Record<string, string> & { categories: Record<string, string> };
     // TODO: Maybe turn this into something that, based on the moduleName, can
     // fetch an ext's actual config type and return that instead.