Small linux fixes

app/src/main/java/io/xpipe/app/core/check/AppFontCheck.java

@@ -8,7 +8,7 @@ public class AppFontCheck {
         try {
             Font.getDefault();
         } catch (Throwable t) {
-            throw new IllegalStateException("Unable to load any fonts. Check whether your system is properly configured with fontconfig", t);
+            throw new IllegalStateException("Unable to load any fonts. Check whether your system is properly configured with fontconfig and you have any fonts installed", t);
         }
     }
 

app/src/main/java/io/xpipe/app/issue/TerminalErrorHandler.java

@@ -26,6 +26,8 @@ public class TerminalErrorHandler extends GuiErrorHandlerBase implements ErrorHa
             handleWithSecondaryException(event, throwable);
             ErrorAction.ignore().handle(event);
         })) {
+            // Exit if we couldn't initialize the GUI
+            OperationMode.halt(1);
             return;
         }