feat(admin): みんなの課題詳細にスタータープロジェクトの DL を表示

スターターはモデレーション対象のコンテンツなのに、admin の詳細は
hasStarter フラグだけで実体を確認できなかった。

- admin Lambda: GET 詳細で content.starterKey を presign して
  starterUrl を返す (無ければ null)
- SPA: 詳細に「スタータープロジェクト (.sb3) をダウンロード」リンク、
  無い場合は「スタータープロジェクトなし」を明示

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: smalruby3-editor-bot[bot]

infra/smalruby-admin/lambda/handler.ts

@@ -328,10 +328,19 @@ async function handleGetSharedAssignment(
         )
       : null,
   })));
+  // The starter project is part of what gets moderated — let the operator
+  // download and inspect the actual .sb3.
+  const starterUrl = content.starterKey
+    ? await getSignedUrl(
+        s3Client,
+        new GetObjectCommand({ Bucket: SHARED_BUCKET, Key: content.starterKey }),
+        { expiresIn: PRESIGNED_URL_DOWNLOAD_EXPIRY },
+      )
+    : null;
 
   return {
     statusCode: 200,
-    body: JSON.stringify({ ...mapSharedItemForAdmin(item), pages }),
+    body: JSON.stringify({ ...mapSharedItemForAdmin(item), pages, starterUrl }),
   };
 }
 

infra/smalruby-admin/lambda/tests/handler.test.ts

@@ -284,6 +284,44 @@ describe('みんなの課題 management (issue #1083)', () => {
     expect(queue[0].item.title).toBe('ねこあつめ入門');
   });
 
+  test('GET detail presigns page images and the starter project', async () => {
+    mockSend.mockImplementation(async (command: {
+      constructor: { name: string }; input?: { TableName?: string };
+    }) => {
+      const name = command.constructor.name;
+      if (name === 'GetCommand' && command.input?.TableName?.includes('Admins')) return adminRow;
+      if (name === 'GetCommand') return { Item: sharedItem };
+      return {};
+    });
+
+    const res = await handler({
+      requestContext: { http: { method: 'GET', path: '/admin/shared-assignments/s1' } },
+      pathParameters: { sharedId: 's1' },
+      headers: { authorization: `Bearer ${DEV_TOKEN}`, origin: 'https://smalruby.app' },
+    });
+    expect(res.statusCode).toBe(200);
+    const body = JSON.parse(res.body as string);
+    expect(body.pages[0].imageUrl).toBe('https://signed.example/get');
+    // The starter is moderated content too — the operator gets a download URL.
+    expect(body.starterUrl).toBe('https://signed.example/get');
+
+    // Without a starterKey the field is null, not a broken link.
+    mockSend.mockImplementation(async (command: {
+      constructor: { name: string }; input?: { TableName?: string };
+    }) => {
+      const name = command.constructor.name;
+      if (name === 'GetCommand' && command.input?.TableName?.includes('Admins')) return adminRow;
+      if (name === 'GetCommand') return { Item: { ...sharedItem, content: { pages: [] } } };
+      return {};
+    });
+    const bare = await handler({
+      requestContext: { http: { method: 'GET', path: '/admin/shared-assignments/s1' } },
+      pathParameters: { sharedId: 's1' },
+      headers: { authorization: `Bearer ${DEV_TOKEN}`, origin: 'https://smalruby.app' },
+    });
+    expect(JSON.parse(bare.body as string).starterUrl).toBeNull();
+  });
+
   test('PATCH flips the status and audits the action', async () => {
     const logs: string[] = [];
     const spy = jest.spyOn(console, 'log').mockImplementation((line: string) => {

packages/admin/src/components/shared-assignments-view.jsx

@@ -94,6 +94,21 @@ const SharedDetail = ({sharedId, onBack, onChanged}) => {
                     >{detail.supplementUrl}</a>
                 </p>
             ) : null}
+            <p
+                className="admin-meta"
+                data-testid="shared-admin-starter"
+            >
+                {detail.starterUrl ? (
+                    <a
+                        data-testid="shared-admin-starter-download"
+                        href={detail.starterUrl}
+                        rel="noopener noreferrer"
+                        target="_blank"
+                    >{'スタータープロジェクト (.sb3) をダウンロード'}</a>
+                ) : (
+                    'スタータープロジェクトなし'
+                )}
+            </p>
             {(detail.pages || []).map((page, index) => (
                 <div
                     className="admin-page"

packages/admin/test/unit/shared-assignments-view.test.jsx

@@ -32,7 +32,8 @@ const detail = {
     tags: ['甲子園'],
     supplementUrl: 'https://docs.google.com/x',
     reuseCount: 4,
-    pages: [{text: 'ページ1', imageUrl: null}]
+    pages: [{text: 'ページ1', imageUrl: null}],
+    starterUrl: 'https://signed.example/starter.sb3'
 };
 
 describe('SharedAssignmentsView (issue #1083)', () => {
@@ -77,6 +78,25 @@ describe('SharedAssignmentsView (issue #1083)', () => {
         await waitFor(() => expect(mockFetchReports.mock.calls.length).toBeGreaterThan(1));
     });
 
+    test('the detail offers the starter download, or says there is none', async () => {
+        const first = render(<SharedAssignmentsView />);
+        await waitFor(() => screen.getByTestId('shared-admin-queue-item-s1'));
+        fireEvent.click(screen.getByTestId('shared-admin-queue-item-s1'));
+        await waitFor(() => screen.getByTestId('shared-admin-detail'));
+        expect(screen.getByTestId('shared-admin-starter-download')).toHaveAttribute(
+            'href', 'https://signed.example/starter.sb3');
+        first.unmount();
+
+        // Without a starter: an explicit "none" note, no dead link.
+        mockFetchDetail.mockResolvedValue({...detail, starterUrl: null});
+        render(<SharedAssignmentsView />);
+        await waitFor(() => screen.getByTestId('shared-admin-queue-item-s1'));
+        fireEvent.click(screen.getByTestId('shared-admin-queue-item-s1'));
+        await waitFor(() => expect(screen.getByTestId('shared-admin-starter').textContent)
+            .toContain('スタータープロジェクトなし'));
+        expect(screen.queryByTestId('shared-admin-starter-download')).not.toBeInTheDocument();
+    });
+
     test('the confirmation can be cancelled without any API call', async () => {
         render(<SharedAssignmentsView />);
         await waitFor(() => screen.getByTestId('shared-admin-queue-item-s1'));