feat(tabs): locate tab objects in sidebar

Closes #6681

apps/desktop/src/lib/sidebar/sidebarActiveTabTarget.ts

@@ -331,30 +331,37 @@ export function shouldScrollActiveSidebarSelection(options: { activeTabId: strin
   return options.activeTabId !== options.previousActiveTabId || (options.autoSelectEnabled && options.previousAutoSelectEnabled === false);
 }
 
-// nearest is used for passive auto-selection; smart keeps context for explicit locate actions.
-export type SidebarNodeScrollAlign = "nearest" | "top" | "smart";
+// nearest is used for passive auto-selection; smart keeps context for the existing toolbar action.
+export type SidebarNodeScrollAlign = "nearest" | "top" | "smart" | "center";
 
-export function scrollTopForSidebarNode(options: { index: number; currentScrollTop: number; viewportHeight: number; rowHeight?: number; topOcclusionHeight?: number; align?: SidebarNodeScrollAlign }): number {
+export function scrollTopForSidebarNode(options: { index: number; currentScrollTop: number; viewportHeight: number; scrollHeight?: number; rowHeight?: number; topOcclusionHeight?: number; align?: SidebarNodeScrollAlign }): number {
   const rowHeight = options.rowHeight ?? SIDEBAR_TREE_ROW_HEIGHT;
   if (options.index < 0 || options.viewportHeight <= 0) return options.currentScrollTop;
 
   const rowTop = options.index * rowHeight;
   const rowBottom = rowTop + rowHeight;
   const topOcclusionHeight = options.topOcclusionHeight ?? 0;
-  if (options.align === "top") return Math.max(0, rowTop - topOcclusionHeight);
+  const maxScrollTop = options.scrollHeight == null ? Number.POSITIVE_INFINITY : Math.max(0, options.scrollHeight - options.viewportHeight);
+  const clampScrollTop = (value: number) => Math.max(0, Math.min(maxScrollTop, value));
+  if (options.align === "top") return clampScrollTop(rowTop - topOcclusionHeight);
   if (options.align === "smart") {
     // Similar to IDE Locate: place the target around the upper third of the viewport.
     const availableViewportHeight = Math.max(rowHeight, options.viewportHeight - topOcclusionHeight);
     const smartOffset = Math.max(0, (availableViewportHeight - rowHeight) / 3);
-    return Math.max(0, Math.round(rowTop - topOcclusionHeight - smartOffset));
+    return clampScrollTop(Math.round(rowTop - topOcclusionHeight - smartOffset));
+  }
+  if (options.align === "center") {
+    const availableViewportHeight = Math.max(rowHeight, options.viewportHeight - topOcclusionHeight);
+    const centerOffset = Math.max(0, (availableViewportHeight - rowHeight) / 2);
+    return clampScrollTop(Math.round(rowTop - topOcclusionHeight - centerOffset));
   }
 
   const viewportTop = options.currentScrollTop + topOcclusionHeight;
   const viewportBottom = options.currentScrollTop + options.viewportHeight;
 
-  if (rowTop < viewportTop) return Math.max(0, rowTop - topOcclusionHeight);
-  if (rowBottom > viewportBottom) return Math.max(0, rowBottom - options.viewportHeight);
-  return options.currentScrollTop;
+  if (rowTop < viewportTop) return clampScrollTop(rowTop - topOcclusionHeight);
+  if (rowBottom > viewportBottom) return clampScrollTop(rowBottom - options.viewportHeight);
+  return clampScrollTop(options.currentScrollTop);
 }
 
 export function findNodePathForActiveTab(tab: QueryTab | undefined | null, treeNodes: readonly TreeNode[]): TreeNode[] | null {