Enlarge crash error dialog for better readability

Widen dialog to 700px, increase height to 500px, use wide layout, and
expand the error output scroll area (250-500px) so more of the stderr
text is visible without scrolling.

src/ui/widgets.rs

@@ -216,7 +216,10 @@ pub fn show_crash_dialog(
         .body(&body)
         .close_response("close")
         .default_response("close")
+        .prefer_wide_layout(true)
         .build();
+    dialog.set_content_width(700);
+    dialog.set_content_height(500);
 
     // Build the full text that gets copied
     let full_error = format!(
@@ -256,8 +259,9 @@ pub fn show_crash_dialog(
 
         let scrolled = gtk::ScrolledWindow::builder()
             .child(&text_view)
-            .min_content_height(120)
-            .max_content_height(300)
+            .min_content_height(250)
+            .max_content_height(500)
+            .vexpand(true)
             .build();
         vbox.append(&scrolled);