Scroll long menus and lists with the mouse wheel or a swipe

Touch clicks in menus happen on release without a swipe. The first-start
language picker is a flag grid that scrolls.

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

src/menu/bestiary.rs

@@ -92,6 +92,16 @@ impl Menu {
         self.page = Some(page);
     }
 
+    // mouse wheel / swipe: the previous or next entry (no wrap-around)
+    pub(super) fn bestiary_wheel(&mut self, d: i32) {
+        let Some(Page::Bestiary { tab, sel, .. }) = self.page else { return };
+        let n = entries(tab).len() as i32;
+        let s = sel as i32 + d;
+        if s >= 0 && s < n {
+            self.bestiary_click(Btn::BestSel(d));
+        }
+    }
+
     pub(super) fn draw_bestiary(&mut self, gfx: &Gfx, tab: usize, sel: usize, level: u32) {
         let (sw, sh) = (sw(), sh());
         let (mx, my) = mouse();