fix(gui): widen Keep Pairs input (80->140) and switch to drag_int

- src/gui_2.py:3829 set_next_item_width 80 -> 140, input_int -> drag_int
- Tests adapted to mock drag_int alongside input_int (5 test files)

tests/test_gui_discussion_tabs.py

@@ -47,6 +47,7 @@ def test_discussion_tabs_rendered(mock_gui):
   mock_imgui.input_text_multiline.return_value = (False, "")
   mock_imgui.checkbox.return_value = (False, False)
   mock_imgui.input_int.return_value = (False, 0)
+  mock_imgui.drag_int.return_value = (False, 0)
   
   mock_clipper = MagicMock()
   mock_clipper.step.return_value = False