Show detailed error information for erroneous documents

- Extract error details from Binect API for documents with status 7
- Display error details in a highlighted box below the status
- Map status 7 (ERRONEOUS) to 'failed' status in refresh handler
- Add CSS styling for error details display

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

src/utils/binect-api.ts

@@ -334,6 +334,7 @@ export interface DocumentStatusInfo {
   statusText: string;
   price?: number;
   recipientAddress?: string;
+  errorDetails?: string;  // Error details for erroneous documents
 }
 
 /**
@@ -425,17 +426,25 @@ export async function getDocumentStatus(
     // Extract price and recipient if available
     let price: number | undefined;
     let recipientAddress: string | undefined;
+    let errorDetails: string | undefined;
 
     if (doc.letter?.letterData) {
       price = doc.letter.letterData.price?.priceAfterTax;
       recipientAddress = doc.letter.letterData.recipientAddress;
     }
 
+    // Extract error details for erroneous documents (status 7)
+    if (doc.status.code === 7 && doc.letter?.errors && doc.letter.errors.length > 0) {
+      errorDetails = doc.letter.errors.map(e => e.message).join('; ');
+      console.log('[Binect API] Document errors:', errorDetails);
+    }
+
     return {
       status: doc.status.code,
       statusText: doc.status.text || getStatusText(doc.status.code),
       price,
       recipientAddress,
+      errorDetails,
     };
   } catch (error) {
     console.error('[Binect API] Get status error:', error);