feat(app): import-agent pill above draft composer (#833)

Surfaces the existing Import-agent sheet directly from the new-agent
draft composer, so users don't have to dig into the workspace header
menu. The pill renders only on draft tabs (gated by the prop being
provided) and reuses the existing WorkspaceImportSheet.

packages/app/src/panels/draft-panel.tsx

@@ -18,8 +18,15 @@ function useDraftPanelDescriptor() {
 }
 
 function DraftPanel() {
-  const { serverId, workspaceId, tabId, target, openFileInWorkspace, retargetCurrentTab } =
-    usePaneContext();
+  const {
+    serverId,
+    workspaceId,
+    tabId,
+    target,
+    openFileInWorkspace,
+    openImportSheet,
+    retargetCurrentTab,
+  } = usePaneContext();
   const { isInteractive } = usePaneFocus();
   invariant(target.kind === "draft", "DraftPanel requires draft target");
 
@@ -52,6 +59,7 @@ function DraftPanel() {
       isPaneFocused={isInteractive}
       onOpenWorkspaceFile={handleOpenWorkspaceFile}
       onCreated={handleCreated}
+      onOpenImportSheet={openImportSheet}
     />
   );
 }

packages/app/src/panels/pane-context.tsx

@@ -11,6 +11,7 @@ export interface PaneContextValue {
   closeCurrentTab: () => void;
   retargetCurrentTab: (target: WorkspaceTabTarget) => void;
   openFileInWorkspace: (filePath: string) => void;
+  openImportSheet: () => void;
 }
 
 export interface PaneFocusContextValue {