fix(scroll): snap to click-time scrollTop before smooth scroll

Capture mainApp.scrollTop synchronously when addStackedNote runs and
snap the scroll back to that value before scrollIntoView fires, so
the smooth scroll begins from where the user actually tapped rather
than from a position drifted by momentum or async work.

src/hooks/useRouteQueryStackedNotes.hook.ts

@@ -114,6 +114,10 @@ export const useRouteQueryStackedNotes = () => {
     selector?: string,
     hash?: string
   ) => {
+    const mainAppEl = document.getElementById("main-app")
+    ;(window as unknown as { __scrollAtClick?: number }).__scrollAtClick =
+      mainAppEl?.scrollTop ?? 0
+
     if (stackedNotes.value.includes(sha)) {
       scrollToFocusedNote({
         noteId: selector ?? sha,