fix sidebar auto scroll on list update

src/composables/useVirtualizerAnchor.js

@@ -0,0 +1,62 @@
+import { nextTick } from 'vue';
+
+export function useVirtualizerAnchor({
+    virtualizer,
+    virtualRows,
+    scrollViewportRef
+}) {
+    const captureScrollAnchor = () => {
+        const viewport = scrollViewportRef.value;
+        const items = virtualizer.value?.getVirtualItems?.() ?? [];
+        if (!viewport || !items.length) {
+            return null;
+        }
+        const firstItem = items[0];
+        const row = virtualRows.value[firstItem.index];
+        const key = row?.key ?? firstItem.key;
+        if (typeof key === 'undefined') {
+            return null;
+        }
+        return {
+            key,
+            offset: viewport.scrollTop - firstItem.start
+        };
+    };
+
+    const restoreScrollAnchor = (anchor) => {
+        if (!anchor) {
+            return;
+        }
+        const index = virtualRows.value.findIndex(
+            (row) => row?.key === anchor.key
+        );
+        if (index === -1) {
+            return;
+        }
+        const offsetInfo = virtualizer.value?.getOffsetForIndex?.(
+            index,
+            'start'
+        );
+        const targetStart = Array.isArray(offsetInfo) ? offsetInfo[0] : null;
+        if (typeof targetStart !== 'number') {
+            return;
+        }
+        virtualizer.value?.scrollToOffset?.(targetStart + anchor.offset);
+    };
+
+    const measureWithAnchor = (measureFn) => {
+        const anchor = captureScrollAnchor();
+        nextTick(() => {
+            if (measureFn) {
+                measureFn();
+            }
+            restoreScrollAnchor(anchor);
+        });
+    };
+
+    return {
+        captureScrollAnchor,
+        restoreScrollAnchor,
+        measureWithAnchor
+    };
+}