Refactor index.astro to improve type safety, enhance UI update functions, and streamline event handling for transactions

src/types/events.ts

@@ -0,0 +1,13 @@
+import type { Transaction } from "../types";
+
+export interface TransactionEventDetail {
+  transaction: Transaction;
+}
+
+declare global {
+  interface WindowEventMap {
+    transactionCreated: CustomEvent<TransactionEventDetail>;
+    transactionUpdated: CustomEvent<TransactionEventDetail>;
+    editTransaction: CustomEvent<TransactionEventDetail>;
+  }
+}