Refuse PDF page ranges in the Place PDF dialog instead of using page 1

Fixes #1337

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/ui-egui/src/dialogs.rs

@@ -3268,6 +3268,14 @@ pub fn confirm(app: &mut DesignApp) -> Result<Value, String> {
         }
         "pdfImport" => {
             let crop = d.s("crop");
+            if !d.s("page").trim().is_empty() && d.n("page").is_none() {
+                // A range or list ("4-5", "2,5") is not a page number: refuse it rather than place page 1.
+                let e = "Enter a single page number; one page is placed at a time".to_string();
+                let mut d = d;
+                d.fields.insert("status".into(), json!(e));
+                app.ui.dialog = Some(d);
+                return Err(e);
+            }
             if d.b("async") {
                 return app.confirm_pdf_import(d.n("page").unwrap_or(1.0).max(1.0) as u64, if crop.is_empty() { "crop".into() } else { crop });
             }

crates/ui-egui/src/lib.rs

@@ -2951,6 +2951,19 @@ mod browser_import_tests {
         assert_eq!(pixels.data().iter().filter(|p| p.r > 240 && p.g < 10 && p.b < 10).count(), 0);
     }
 
+    #[test]
+    fn pdf_options_refuse_a_page_range_instead_of_placing_page_one() {
+        for spec in ["4-5", "2,5", "2-3"] {
+            let mut app = app();
+            let request = app.import_request("place");
+            deliver(&mut app, request, "three.pdf", pdf());
+            app.ui.dialog.as_mut().unwrap().fields.insert("page".into(), json!(spec));
+            assert!(dialogs::confirm(&mut app).is_err(), "{spec}");
+            assert!(app.session.doc().unwrap().doc.assets.is_empty(), "{spec}");
+            assert_eq!(app.ui.dialog.as_ref().unwrap().id, "pdfImport", "{spec}");
+        }
+    }
+
     #[test]
     fn place_loads_the_cursor_unless_a_frame_can_take_the_graphic() {
         let mut app = app();