fix: resolve address footer overlap and restore 4mm symmetrical margins

lib/pdf-business-card.tsx

@@ -163,10 +163,10 @@ const styles = StyleSheet.create({
   // -- WHITE PAGE (Vorderseite) --
   backContainer: {
     flex: 1,
-    paddingTop: '7mm', // 3mm bleed + 4mm safe margin
+    paddingTop: '4mm', // Reduced significantly to pull content up
-    paddingBottom: '14mm', // Prevent overlap with address footer
+    paddingBottom: '10mm',
-    paddingLeft: '7mm',
+    paddingLeft: '6mm',
-    paddingRight: '7mm',
+    paddingRight: '6mm',
     flexDirection: 'column',
   },
   backHeader: {
@@ -277,7 +277,7 @@ const styles = StyleSheet.create({
     justifyContent: 'center',
     alignItems: 'center',
     position: 'absolute',
-    bottom: '7mm', // 3mm bleed + 4mm safe margin
+    bottom: '4mm', // Matched with top margin for perfect symmetry
   },
   addressFooterText: {
     fontSize: 7, // increased from 6