fix(pdf): resolve crash in yoga engine caused by absolute positioning and empty paragraphs

lib/pdf-page.tsx

@@ -1,3 +1,4 @@
+import React from 'react';
 /* eslint-disable react/prop-types */
 import { Document, Page, View, Text, StyleSheet, Link, Image } from '@react-pdf/renderer';
 
@@ -240,6 +241,7 @@ const renderLexicalNode = (node: any, idx: number): React.ReactNode => {
     }
 
     case 'paragraph': {
+      if (!node.children || node.children.length === 0) return null;
       return (
         <Text key={idx} style={styles.paragraph}>
           {node.children?.map((child: any, i: number) => renderLexicalNode(child, i))}
@@ -248,6 +250,7 @@ const renderLexicalNode = (node: any, idx: number): React.ReactNode => {
     }
 
     case 'heading': {
+      if (!node.children || node.children.length === 0) return null;
       let hStyle = styles.heading3;
       let isH1 = false;
       if (node.tag === 'h1') {
@@ -274,6 +277,7 @@ const renderLexicalNode = (node: any, idx: number): React.ReactNode => {
     }
 
     case 'list': {
+      if (!node.children || node.children.length === 0) return null;
       return (
         <View key={idx} style={styles.list}>
           {node.children?.map((child: any, i: number) => {
@@ -365,7 +369,7 @@ export const PDFPage: React.FC<PDFPageProps> = ({ page, locale = 'de' }) => {
         </View>
 
         {/* Industrial footer with page numbers */}
-        <View style={styles.footer} fixed>
+        <View style={{ ...styles.footer, position: 'absolute', bottom: 30, height: 40 }} fixed>
           <View style={styles.footerInfo}>
             <Text style={styles.footerBrand}>KLZ VERTRIEBS GMBH</Text>
             <Text style={styles.footerText}>