fix(workflow): make FileTree and ArtifactsSection scroll independently

The sidebar layout was broken when ArtifactsSection expanded - it would
squeeze the FileTree and neither area could scroll. This restructures the
layout so each section has its own scroll container with proper height
constraints.

web/app/components/workflow/skill/file-tree/artifacts-section.tsx

@@ -45,45 +45,47 @@ const ArtifactsSection: FC<ArtifactsSectionProps> = ({ className }) => {
   const showSpinner = isLoading
 
   return (
-    <div className={cn('shrink-0 border-t border-divider-regular p-1', className)}>
-      <button
-        type="button"
-        onClick={handleToggle}
-        className={cn(
-          'flex w-full items-center rounded-md py-1 pl-2 pr-1.5',
-          'hover:bg-state-base-hover',
-          'focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-components-input-border-active',
-        )}
-        aria-expanded={isExpanded}
-        aria-label={t('skillSidebar.artifacts.openArtifacts')}
-      >
-        <div className="flex flex-1 items-center gap-1 py-0.5">
-          <div className="flex size-5 items-center justify-center">
-            <FolderSpark className="size-4 text-text-secondary" aria-hidden="true" />
+    <div className={cn('flex max-h-[40%] flex-col border-t border-divider-regular', className)}>
+      <div className="shrink-0 p-1">
+        <button
+          type="button"
+          onClick={handleToggle}
+          className={cn(
+            'flex w-full items-center rounded-md py-1 pl-2 pr-1.5',
+            'hover:bg-state-base-hover',
+            'focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-components-input-border-active',
+          )}
+          aria-expanded={isExpanded}
+          aria-label={t('skillSidebar.artifacts.openArtifacts')}
+        >
+          <div className="flex flex-1 items-center gap-1 py-0.5">
+            <div className="flex size-5 items-center justify-center">
+              <FolderSpark className="size-4 text-text-secondary" aria-hidden="true" />
+            </div>
+            <span className="system-sm-semibold uppercase text-text-secondary">
+              {t('skillSidebar.artifacts.title')}
+            </span>
           </div>
-          <span className="system-sm-semibold uppercase text-text-secondary">
-            {t('skillSidebar.artifacts.title')}
-          </span>
-        </div>
 
-        <div className="relative flex items-center">
-          {showSpinner
-            ? <RiLoader2Line className="size-3.5 animate-spin text-text-tertiary" aria-hidden="true" />
-            : (
-                <>
-                  {showBlueDot && (
-                    <div className="absolute -left-2 size-[7px] rounded-full border border-white bg-state-accent-solid" />
-                  )}
-                  {isExpanded
-                    ? <RiArrowDownSLine className="size-4 text-text-tertiary" aria-hidden="true" />
-                    : <RiArrowRightSLine className="size-4 text-text-tertiary" aria-hidden="true" />}
-                </>
-              )}
-        </div>
-      </button>
+          <div className="relative flex items-center">
+            {showSpinner
+              ? <RiLoader2Line className="size-3.5 animate-spin text-text-tertiary" aria-hidden="true" />
+              : (
+                  <>
+                    {showBlueDot && (
+                      <div className="absolute -left-2 size-[7px] rounded-full border border-white bg-state-accent-solid" />
+                    )}
+                    {isExpanded
+                      ? <RiArrowDownSLine className="size-4 text-text-tertiary" aria-hidden="true" />
+                      : <RiArrowRightSLine className="size-4 text-text-tertiary" aria-hidden="true" />}
+                  </>
+                )}
+          </div>
+        </button>
+      </div>
 
       {isExpanded && !isLoading && (
-        <div className="flex flex-col gap-px">
+        <div className="min-h-0 flex-1 overflow-y-auto px-1 pb-1">
           {hasFiles
             ? (
                 <ArtifactsTree
@@ -93,7 +95,7 @@ const ArtifactsSection: FC<ArtifactsSectionProps> = ({ className }) => {
                 />
               )
             : (
-                <div className="px-2.5 pb-1.5 pt-0.5">
+                <div className="px-1.5 pb-0.5">
                   <div className="rounded-lg bg-background-section p-3">
                     <p className="system-xs-regular text-text-tertiary">
                       {t('skillSidebar.artifacts.emptyState')}

web/app/components/workflow/skill/file-tree/index.tsx

@@ -25,7 +25,6 @@ import { useSkillAssetTreeData } from '../hooks/use-skill-asset-tree'
 import { useSkillShortcuts } from '../hooks/use-skill-shortcuts'
 import { useSyncTreeWithActiveTab } from '../hooks/use-sync-tree-with-active-tab'
 import { isDescendantOf } from '../utils/tree-utils'
-import ArtifactsSection from './artifacts-section'
 import DragActionTooltip from './drag-action-tooltip'
 import TreeContextMenu from './tree-context-menu'
 import TreeNode from './tree-node'
@@ -235,41 +234,34 @@ const FileTree: React.FC<FileTreeProps> = ({ className }) => {
 
   if (treeChildren.length === 0 && !hasPendingCreate) {
     return (
-      <>
-        <div className={cn('flex min-h-0 flex-1 flex-col', className)}>
-          <div className="flex flex-1 flex-col items-center justify-center gap-2 px-4 text-center">
-            <span className="system-xs-regular text-text-tertiary">
-              {t('skillSidebar.empty')}
-            </span>
-          </div>
-          <DropTip />
+      <div className={cn('flex min-h-[150px] flex-1 flex-col overflow-y-auto', className)}>
+        <div className="flex flex-1 flex-col items-center justify-center gap-2 px-4 text-center">
+          <span className="system-xs-regular text-text-tertiary">
+            {t('skillSidebar.empty')}
+          </span>
         </div>
-        <ArtifactsSection />
-      </>
+        <DropTip />
+      </div>
     )
   }
 
-  // Search has no matching results
   if (hasSearchNoResults) {
     return (
-      <>
-        <div className={cn('flex min-h-0 flex-1 flex-col', className)}>
-          <div className="flex flex-1 flex-col items-center justify-center gap-2 pb-20">
-            <SearchMenu className="size-8 text-text-tertiary" aria-hidden="true" />
-            <span className="system-xs-regular text-text-secondary">
-              {t('skillSidebar.searchNoResults')}
-            </span>
-            <Button
-              variant="secondary-accent"
-              size="small"
-              onClick={() => storeApi.getState().setFileTreeSearchTerm('')}
-            >
-              {t('skillSidebar.resetFilter')}
-            </Button>
-          </div>
+      <div className={cn('flex min-h-[150px] flex-1 flex-col overflow-y-auto', className)}>
+        <div className="flex flex-1 flex-col items-center justify-center gap-2 pb-20">
+          <SearchMenu className="size-8 text-text-tertiary" aria-hidden="true" />
+          <span className="system-xs-regular text-text-secondary">
+            {t('skillSidebar.searchNoResults')}
+          </span>
+          <Button
+            variant="secondary-accent"
+            size="small"
+            onClick={() => storeApi.getState().setFileTreeSearchTerm('')}
+          >
+            {t('skillSidebar.resetFilter')}
+          </Button>
         </div>
-        <ArtifactsSection />
-      </>
+      </div>
     )
   }
 
@@ -278,7 +270,7 @@ const FileTree: React.FC<FileTreeProps> = ({ className }) => {
       <div
         data-skill-tree-container
         className={cn(
-          'flex min-h-0 flex-1 flex-col',
+          'flex min-h-[150px] flex-1 flex-col overflow-y-auto',
           isMutating && 'pointer-events-none opacity-50',
           className,
         )}
@@ -287,7 +279,6 @@ const FileTree: React.FC<FileTreeProps> = ({ className }) => {
           ref={containerRef}
           className={cn(
             'flex min-h-0 flex-1 flex-col overflow-hidden px-1 pt-1',
-            // Root dropzone highlight - dashed border without layout shift
             isRootDropzone && 'relative rounded-lg bg-state-accent-hover after:pointer-events-none after:absolute after:inset-0 after:rounded-lg after:border-[1.5px] after:border-dashed after:border-state-accent-solid after:content-[\'\']',
           )}
           onClick={handleBlankAreaClick}
@@ -321,11 +312,10 @@ const FileTree: React.FC<FileTreeProps> = ({ className }) => {
             {renderTreeNode}
           </Tree>
         </div>
+        {dragOverFolderId
+          ? <DragActionTooltip action={currentDragType ?? 'upload'} />
+          : <DropTip />}
       </div>
-      {dragOverFolderId
-        ? <DragActionTooltip action={currentDragType ?? 'upload'} />
-        : <DropTip />}
-      <ArtifactsSection />
       <TreeContextMenu treeRef={treeRef} />
     </>
   )

web/app/components/workflow/skill/main.tsx

@@ -8,6 +8,7 @@ import ContentBody from './content-body'
 import FileContentPanel from './file-content-panel'
 import FileTabs from './file-tabs'
 import FileTree from './file-tree'
+import ArtifactsSection from './file-tree/artifacts-section'
 import { useSkillAutoSave } from './hooks/use-skill-auto-save'
 import { SkillSaveProvider } from './hooks/use-skill-save-manager'
 import Sidebar from './sidebar'
@@ -31,6 +32,7 @@ const SkillMain: FC = () => {
           <Sidebar>
             <SidebarSearchAdd />
             <FileTree />
+            <ArtifactsSection />
           </Sidebar>
           <ContentArea>
             <FileTabs />

web/app/components/workflow/skill/sidebar.tsx

@@ -5,7 +5,7 @@ type SidebarProps = PropsWithChildren
 
 const Sidebar: FC<SidebarProps> = ({ children }) => {
   return (
-    <aside className="flex w-[320px] shrink-0 flex-col gap-px overflow-hidden rounded-[10px] border border-components-panel-border-subtle bg-components-panel-bg">
+    <aside className="flex h-full w-[320px] shrink-0 flex-col gap-px overflow-hidden rounded-[10px] border border-components-panel-border-subtle bg-components-panel-bg">
       {children}
     </aside>
   )