fix vtabbar width across the workspace. fix add tab button

Author: sawka

frontend/app/tab/vtabbar.tsx

@@ -245,7 +245,7 @@ export function VTabBar({ workspace, className }: VTabBarProps) {
         >
             <div
                 ref={scrollContainerRef}
-                className="relative flex min-h-0 flex-1 flex-col overflow-y-auto"
+                className="relative flex min-h-0 flex-col overflow-y-auto"
                 onDragOver={(event) => {
                     event.preventDefault();
                     updateScrollFromDragY(event.clientY);

frontend/app/workspace/workspace-layout-model.ts

@@ -265,6 +265,14 @@ class WorkspaceLayoutModel {
 
     // ---- Registration & sync ----
 
+    syncVTabWidthFromMeta(): void {
+        const savedVTabWidth = globalStore.get(this.getVTabBarWidthAtom());
+        if (savedVTabWidth != null && savedVTabWidth > 0 && savedVTabWidth !== this.vtabWidth) {
+            this.vtabWidth = savedVTabWidth;
+            this.commitLayouts(window.innerWidth);
+        }
+    }
+
     registerRefs(
         aiPanelRef: ImperativePanelHandle,
         outerPanelGroupRef: ImperativePanelGroupHandle,

frontend/app/workspace/workspace.tsx

@@ -74,6 +74,12 @@ const WorkspaceElem = memo(() => {
         return () => window.removeEventListener("resize", workspaceLayoutModel.handleWindowResize);
     }, []);
 
+    useEffect(() => {
+        const handleFocus = () => workspaceLayoutModel.syncVTabWidthFromMeta();
+        window.addEventListener("focus", handleFocus);
+        return () => window.removeEventListener("focus", handleFocus);
+    }, []);
+
     const innerHandleVisible = vtabVisible && aiPanelVisible;
     const innerHandleClass = `bg-transparent hover:bg-zinc-500/20 transition-colors ${innerHandleVisible ? "w-0.5" : "w-0 pointer-events-none"}`;
     const outerHandleVisible = vtabVisible || aiPanelVisible;