Fix timezone display issues with formatted dates

Fixes #88

Also update Deno, hoping it might help with #87, but it's unlikely

components/expenses/ListExpenses.tsx

@@ -13,10 +13,17 @@ export default function ListExpenses(
     onClickEditExpense,
   }: ListExpensesProps,
 ) {
-  const dateFormat = new Intl.DateTimeFormat('en-US', {
+  const dateFormatOptions: Intl.DateTimeFormatOptions = {
     month: 'short',
     day: 'numeric',
-  });
+  };
+
+  // Force timeZone to UTC for the server rendering
+  if (typeof window === 'undefined') {
+    dateFormatOptions.timeZone = 'UTC';
+  }
+
+  const dateFormat = new Intl.DateTimeFormat('en-US', dateFormatOptions);
 
   return (
     <section class='mx-auto max-w-7xl my-8 mt-12'>

components/expenses/MainExpenses.tsx

@@ -63,7 +63,18 @@ export default function MainExpenses({ initialBudgets, initialExpenses, initialM
   const shouldResetBudgetModal = useSignal<boolean>(false);
   const searchTimeout = useSignal<ReturnType<typeof setTimeout>>(0);
 
-  const dateFormat = new Intl.DateTimeFormat('en-GB', { year: 'numeric', month: 'long' });
+  const dateFormatOptions: Intl.DateTimeFormatOptions = {
+    year: 'numeric',
+    month: 'long',
+  };
+
+  // Force timeZone to UTC for the server rendering
+  if (typeof window === 'undefined') {
+    dateFormatOptions.timeZone = 'UTC';
+  }
+
+  const dateFormat = new Intl.DateTimeFormat('en-GB', dateFormatOptions);
+
   const thisMonth = new Date().toISOString().substring(0, 7);
 
   function onClickImportFile() {