feat: add job details modal for Letzshop jobs tab

- Replace browser alert with proper modal for job details view
- Show job info, status, records, timestamps in modal
- Display export file details (languages, file sizes) for export jobs
- Include error_details in API response for export and order_sync jobs
- Add selectedJobDetails state and showJobDetailsModal flag

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

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

static/admin/js/marketplace-letzshop.js

@@ -129,7 +129,9 @@ function adminMarketplaceLetzshop() {
         showTrackingModal: false,
         showOrderModal: false,
         showResolveModal: false,
+        showJobDetailsModal: false,
         selectedOrder: null,
+        selectedJobDetails: null,
         selectedExceptionForResolve: null,
         trackingForm: { tracking_number: '', tracking_provider: '' },
         resolveForm: { product_id: null, product_name: '', notes: '', bulk_resolve: false },
@@ -1412,12 +1414,12 @@ function adminMarketplaceLetzshop() {
         },
 
         /**
-         * View job details
+         * View job details in modal
          */
         viewJobDetails(job) {
-            // For now, just log - could open a modal
             marketplaceLetzshopLog.info('View job details:', job);
-            alert(`Job #${job.id}\nType: ${job.type}\nStatus: ${job.status}\nRecords: ${job.records_succeeded}/${job.records_processed}`);
+            this.selectedJobDetails = job;
+            this.showJobDetailsModal = true;
         },
 
         /**