Preview viewer: don't show stack trace to users (#14231)

* Don't show stack trace to users

* IntelliJ reformat

Author: subhramit

jabgui/src/main/java/org/jabref/gui/preview/PreviewViewer.java

@@ -1,8 +1,6 @@
 package org.jabref.gui.preview;
 
 import java.io.IOException;
-import java.io.PrintWriter;
-import java.io.StringWriter;
 import java.net.MalformedURLException;
 import java.util.List;
 import java.util.Objects;
@@ -210,13 +208,17 @@ private void update() {
     }
 
     private String formatError(BibEntry entry, Throwable exception) {
-        StringWriter sw = new StringWriter();
-        exception.printStackTrace(new PrintWriter(sw));
-        return "%s\n\n%s\n\nBibTeX (internal):\n%s\n\nStack Trace:\n%s".formatted(
+        LOGGER.error("Error generating preview for entry: {}", entry.getCitationKey(), exception);
+
+        return """
+                <div class="error">
+                    <h3>%s</h3>
+                    <p>%s</p>
+                    <p><small>Check the event logs for details.</small></p>
+                </div>
+                """.formatted(
                 Localization.lang("Error while generating citation style"),
-                exception.getLocalizedMessage(),
-                entry,
-                sw);
+                exception.getLocalizedMessage() != null ? exception.getLocalizedMessage() : "Unknown error");
     }
 
     private void setPreviewText(String text) {