feat: add informational message for bulk auto-match operation

- Show confirmation dialog before starting auto-match operation
- Inform users that it's a bulk operation processing entire photo library
- Warn that some matches may not be 100% accurate
- Recommend reviewing results after completion

admin-frontend/src/pages/AutoMatch.tsx

@@ -449,6 +449,22 @@ export default function AutoMatch() {
       return
     }
 
+    // Show informational message about bulk operation
+    const infoMessage = [
+      'ℹ️ Bulk Auto-Match Operation',
+      '',
+      'This operation will automatically match faces across your entire photo library.',
+      'While the system uses advanced matching algorithms, some matches may not be 100% accurate.',
+      '',
+      'Please review the results after completion to ensure accuracy.',
+      '',
+      'Do you want to proceed with the auto-match operation?'
+    ].join('\n')
+
+    if (!confirm(infoMessage)) {
+      return
+    }
+
     setBusy(true)
     try {
       const response = await facesApi.autoMatch({