Fix: Update button remaining disabled in transaction edit mode

This commit resolves an issue where the Update button in the transaction form
would remain disabled when attempting to edit a transaction. The problem was
in how the transactionStore was managing state updates during transaction editing.

Key changes:
- Enhanced startEditingTransaction function in transactionStore.ts to ensure proper reactivity
- Added clean copy creation of transaction objects to avoid reference issues
- Implemented a state update cycle with null value first to force reactivity
- Added a small timeout to ensure state changes are properly detected by components

The Transaction form now correctly enables the Update button when in edit mode,
regardless of account selection state.

src/pages/api/transactions/index.ts

@@ -11,7 +11,7 @@
  */
 
 import type { APIRoute } from 'astro';
-import { accounts, transactions } from '../../../data/store';
+import { accountService, transactionService } from '../../../data/db.service';
 import type { Transaction } from '../../../types';
 
 /**
@@ -43,7 +43,7 @@ export const POST: APIRoute = async ({ request }) => {
     }
 
     // Validate account exists
-    const account = accounts.find((a) => a.id === transaction.accountId);
+    const account = await accountService.getById(transaction.accountId);
     if (!account) {
       return new Response(JSON.stringify({ error: 'Account not found' }), {
         status: 404,
@@ -51,25 +51,32 @@ export const POST: APIRoute = async ({ request }) => {
       });
     }
 
-    // Create new transaction with generated ID
-    const newTransaction: Transaction = {
-      ...transaction,
-      id: (transactions.length + 1).toString(), // Simple ID generation for demo
-    };
+    // Convert string date to Date object if needed
+    const transactionDate =
+      typeof transaction.date === 'string' ? new Date(transaction.date) : transaction.date;
 
-    // Update account balance
-    account.balance += transaction.amount;
-
-    // Add to transactions array
-    transactions.push(newTransaction);
+    // Create new transaction with database service
+    // The database service will also update the account balance
+    const newTransaction = await transactionService.create({
+      accountId: transaction.accountId,
+      date: transactionDate,
+      description: transaction.description,
+      amount: transaction.amount,
+      category: transaction.category,
+      status: transaction.status as any,
+      type: transaction.type as any,
+      notes: transaction.notes,
+      tags: transaction.tags,
+    });
 
     return new Response(JSON.stringify(newTransaction), {
       status: 201,
       headers: { 'Content-Type': 'application/json' },
     });
   } catch (error) {
-    return new Response(JSON.stringify({ error: 'Invalid request body' }), {
-      status: 400,
+    console.error('Error creating transaction:', error);
+    return new Response(JSON.stringify({ error: 'Failed to create transaction' }), {
+      status: 500,
       headers: { 'Content-Type': 'application/json' },
     });
   }