Confirm raw upload responses

server/public/app.js

@@ -915,11 +915,31 @@ async function uploadFileList(win, files, targetPath) {
     } else {
       recordDebug('csrf.missing', {});
     }
-    await fetchChecked(apiUrl(`upload.php?${params.toString()}`), {
+    const response = await fetch(apiUrl(`upload.php?${params.toString()}`), {
       method: 'POST',
       headers: { 'Content-Type': 'application/octet-stream' },
       body: item.file
     });
+    const text = await response.text();
+    recordDebug('upload.file.response', {
+      path: item.path,
+      status: response.status,
+      ok: response.ok,
+      contentType: response.headers.get('content-type'),
+      body: text.slice(0, 1000)
+    });
+    if (!response.ok) {
+      throw new Error(text || `${response.status} ${response.statusText}`);
+    }
+    let payload;
+    try {
+      payload = JSON.parse(text);
+    } catch (error) {
+      throw new Error(`Upload lieferte keine JSON-Antwort: ${text.slice(0, 200) || response.headers.get('content-type') || 'leer'}`);
+    }
+    if (!payload.uploaded?.length) {
+      throw new Error('Upload wurde vom Server nicht bestätigt.');
+    }
     recordDebug('upload.file.done', { path: item.path, index: index + 1, total: uploadItems.length });
   }
   await loadExplorer(win, targetPath);