Implement ISBN live validation and automatic lookup on input change

Web/templates/upload_admin.html

@@ -1067,6 +1067,24 @@
         return false;
     }
 
+    function handleIsbnLookupFromScanner() {
+        const isbnField = document.getElementById('isbn');
+        if (!isbnField) return false;
+
+        const normalizedIsbn = typeof normalizeIsbnClient === 'function' ? normalizeIsbnClient(isbnField.value) : isbnField.value.trim();
+        if (!normalizedIsbn) return false;
+
+        if (typeof updateIsbnLiveValidation === 'function') {
+            updateIsbnLiveValidation();
+        }
+
+        if (typeof fetchBookInfo === 'function') {
+            fetchBookInfo('upload');
+        }
+
+        return true;
+    }
+
     document.addEventListener('DOMContentLoaded', function () {
         document.querySelectorAll('form').forEach(function (form) {
             form.addEventListener('keydown', function (event) {
@@ -1079,6 +1097,12 @@
                 if (['button', 'submit', 'reset', 'file', 'checkbox', 'radio', 'hidden'].includes(type)) return;
 
                 event.preventDefault();
+
+                if (target.id === 'isbn' || target.name === 'isbn') {
+                    handleIsbnLookupFromScanner();
+                    return;
+                }
+
                 focusNextFormField(target);
             });
         });
@@ -1445,11 +1469,33 @@
             scanModeSelect.addEventListener('change', toggleScanMode);
         }
 
-        // 4. ISBN Live-Validierung
+        // 4. ISBN Live-Validierung und automatische Abfrage nach Scan/Enter
         const isbnInput = document.getElementById('isbn');
-        if (isbnInput && typeof updateIsbnLiveValidation === 'function') {
+        if (isbnInput) {
+            if (typeof updateIsbnLiveValidation === 'function') {
                 isbnInput.addEventListener('input', updateIsbnLiveValidation);
             }
+
+            let isbnLookupTimer = null;
+            isbnInput.addEventListener('input', function () {
+                clearTimeout(isbnLookupTimer);
+                const normalizedIsbn = typeof normalizeIsbnClient === 'function' ? normalizeIsbnClient(isbnInput.value) : isbnInput.value.trim();
+                if (normalizedIsbn) {
+                    isbnLookupTimer = setTimeout(function () {
+                        handleIsbnLookupFromScanner();
+                    }, 250);
+                }
+            });
+
+            isbnInput.addEventListener('change', function () {
+                if (typeof normalizeIsbnClient === 'function') {
+                    const normalizedIsbn = normalizeIsbnClient(isbnInput.value);
+                    if (normalizedIsbn) {
+                        handleIsbnLookupFromScanner();
+                    }
+                }
+            });
+        }
     });
     // Load predefined filter values for dropdowns
     function loadPredefinedFilterValues(filterNumber) {