Add OpenAI API integration and document processing features

- Added OpenAI API key configuration to .env.example.
- Integrated OpenAI for document processing, including markdown conversion and data extraction.
- Implemented new API routes for fetching document processing status and handling various processing tasks.
- Enhanced the App component to manage document status and processing states with user feedback via Snackbar.
- Updated CSVImportPanel and TableManagement components to support navigation to specific tabs based on processing results.
- Introduced transaction handling in the database configuration for improved error management during document processing.

client/src/components/CSVImportDialog.js

@@ -56,6 +56,20 @@ class CSVImportPanel extends Component {
     this.datevFileInputRef = React.createRef();
   }
 
+  componentDidMount() {
+    // Check if we should navigate to a specific tab
+    if (this.props.targetTab) {
+      this.setState({ activeTab: this.props.targetTab });
+    }
+  }
+
+  componentDidUpdate(prevProps) {
+    // Handle targetTab changes
+    if (this.props.targetTab !== prevProps.targetTab && this.props.targetTab) {
+      this.setState({ activeTab: this.props.targetTab });
+    }
+  }
+
   // Tab switch resets type-specific state but keeps success state as-is
   handleTabChange = (_e, value) => {
     this.setState({
@@ -344,6 +358,7 @@ class CSVImportPanel extends Component {
         )}
 
         {currentHeaders && (
+          
           <Box sx={{ mb: 2 }}>
             <Typography variant="subtitle2" gutterBottom>
               Erkannte Spalten ({currentHeaders.length}):