fix(stacked-note): size mobile notes with svh to stabilize scroll target

Dynamic viewport units rescale every note when the mobile address bar
grows or shrinks, shifting the scroll target by the address-bar height
mid-flight. Small viewport units stay constant across address-bar
transitions so the smooth scroll lands where it was aimed.

src/components/FluxNote.vue

@@ -259,7 +259,7 @@ $header-height: 40px;
 
   .note {
     width: 100vw;
-    height: 100dvh;
+    height: 100svh;
     overflow-y: visible;
   }