refactor: decouple core-events registry by implementing consumer-side TypeScript module augmentation and reorganizing showcase demos

packages/core-events/src/index.ts

@@ -1,11 +1,5 @@
 // ─── Event Registry ─────────────────────────────────────────────
-export type {
-  AppEvents,
-  PrintReceiptPayload,
-  StockUpdatePayload,
-  ProfileUpdatedPayload,
-  ReceiptItem,
-} from './events.registry';
+export type { AppEventRegistry, AppEvents } from './events.registry';
 
 // ─── Event Bus (Core) ───────────────────────────────────────────
 export { eventBus, publish, subscribe } from './event-bus';