Await render() in renderTasks/renderSingleTask to prevent dangling promises

The previous pattern resolved the caller's promise from the onComplete
callback, which fires before unmountInk() is scheduled. This left the
render() promise dangling, causing test timeouts in theme-downloader tests.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: nickwesselman

.changeset/cool-papers-behave.md

@@ -2,4 +2,4 @@
 '@shopify/app': patch
 ---
 
-[fix] Task progress bars once again clear when complete
+Task progress bars once again clear when complete

packages/cli-kit/src/public/node/ui.tsx

@@ -486,15 +486,26 @@ interface RenderTasksOptions {
 export async function renderTasks<TContext>(
   tasks: Task<TContext>[],
   {renderOptions, noProgressBar}: RenderTasksOptions = {},
-) {
-  return new Promise<TContext>((resolve, reject) => {
-    render(<Tasks tasks={tasks} onComplete={resolve} noProgressBar={noProgressBar} />, {
+): Promise<TContext> {
+  let result: TContext | undefined
+  let taskError: Error | undefined
+  await render(
+    <Tasks
+      tasks={tasks}
+      onComplete={(ctx) => {
+        result = ctx
+      }}
+      noProgressBar={noProgressBar}
+    />,
+    {
       ...renderOptions,
       exitOnCtrlC: false,
-    })
-      .then(() => {})
-      .catch(reject)
+    },
+  ).catch((error) => {
+    taskError = error
   })
+  if (taskError) throw taskError
+  return result as TContext
 }
 
 export interface RenderSingleTaskOptions<T> {
@@ -521,12 +532,29 @@ export async function renderSingleTask<T>({
   onAbort,
   renderOptions,
 }: RenderSingleTaskOptions<T>): Promise<T> {
-  return new Promise<T>((resolve, reject) => {
-    render(<SingleTask title={title} task={task} onComplete={resolve} onError={reject} onAbort={onAbort} />, {
+  let result: T | undefined
+  let taskError: Error | undefined
+  await render(
+    <SingleTask
+      title={title}
+      task={task}
+      onComplete={(innerResult) => {
+        result = innerResult
+      }}
+      onError={(error) => {
+        taskError = error
+      }}
+      onAbort={onAbort}
+    />,
+    {
       ...renderOptions,
       exitOnCtrlC: false,
-    }).catch(reject)
+    },
+  ).catch((error) => {
+    taskError ??= error
   })
+  if (taskError) throw taskError
+  return result as T
 }
 
 export interface RenderTextPromptOptions extends Omit<TextPromptProps, 'onSubmit'> {