Add CSV export functionality for admin orders

- Created exportCSV utility with convertToCSV, downloadCSV, formatExportDate, formatExportIDR
- Added export button to AdminOrders page with loading state
- Export includes all order fields: ID, email, total, status, payment method, date, refund info
- CSV format compatible with Excel and Google Sheets

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/lib/exportCSV.ts

@@ -0,0 +1,62 @@
+/**
+ * Export utility functions for CSV export
+ */
+
+/**
+ * Convert data array to CSV format
+ */
+export const convertToCSV = (data: Record<string, any>[], headers: string[]): string => {
+  // Add headers
+  const csvRows = [headers.join(',')];
+
+  // Add data rows
+  data.forEach((row) => {
+    const values = headers.map((header) => {
+      const value = row[header];
+      // Escape values that contain commas, quotes, or newlines
+      if (value === null || value === undefined) {
+        return '';
+      }
+      const stringValue = String(value);
+      if (stringValue.includes(',') || stringValue.includes('"') || stringValue.includes('\n')) {
+        return `"${stringValue.replace(/"/g, '""')}"`;
+      }
+      return stringValue;
+    });
+    csvRows.push(values.join(','));
+  });
+
+  return csvRows.join('\n');
+};
+
+/**
+ * Trigger CSV download in browser
+ */
+export const downloadCSV = (csv: string, filename: string) => {
+  const blob = new Blob([csv], { type: 'text/csv;charset=utf-8;' });
+  const link = document.createElement('a');
+  const url = URL.createObjectURL(blob);
+
+  link.setAttribute('href', url);
+  link.setAttribute('download', filename);
+  link.style.visibility = 'hidden';
+
+  document.body.appendChild(link);
+  link.click();
+  document.body.removeChild(link);
+};
+
+/**
+ * Format date for export (YYYY-MM-DD HH:mm:ss)
+ */
+export const formatExportDate = (date: string | Date): string => {
+  const d = typeof date === 'string' ? new Date(date) : date;
+  return d.toISOString().replace('T', ' ').substring(0, 19);
+};
+
+/**
+ * Format IDR for export (without "Rp" prefix for easier Excel processing)
+ */
+export const formatExportIDR = (amount: number): string => {
+  return (amount / 100).toLocaleString('id-ID');
+};