feat(m10): file sharing with upload, lightbox, permission, tests, e2e

- FileRepository (CRUD, soft-delete, pagination, project isolation) +
  FileStorageService (local FS save data/uploads/<projectId>/<uuid>.<ext>,
  MIME allowlist, filename sanitize, unique uuid name, member permission,
  file_shared notification to other members, file_uploaded activity log,
  SSE file.uploaded, uploader/admin delete + FS unlink)
- APIs: files list/upload(multipart), download (membership), delete
- Screens: files page + Uploader(multipart) + FileList(image Lightbox,
  PDF link, delete), ProjectNav ファイル link
- Unit tests (FileRepository, FileStorageService) + e2e file-sharing

tests/e2e/file-sharing.spec.ts

@@ -0,0 +1,68 @@
+import { test, expect } from '@playwright/test';
+
+function unique(prefix: string): string {
+  return `${prefix}-${Date.now()}-${Math.floor(Math.random() * 1_000_000)}`;
+}
+
+// 1x1 透明PNG
+const PNG_BUFFER = Buffer.from(
+  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=',
+  'base64'
+);
+
+async function setupOwner(page: import('@playwright/test').Page) {
+  const email = unique('owner') + '@example.com';
+  await page.goto('/login');
+  await page.getByRole('button', { name: '新規登録はこちら' }).click();
+  await page.getByLabel('表示名').fill('Owner');
+  await page.getByLabel('メールアドレス').fill(email);
+  await page.getByLabel('パスワード').fill('password123');
+  await page.getByRole('button', { name: '登録する' }).click();
+  await expect(page).toHaveURL(/\/dashboard/);
+  await page.getByLabel('プロジェクト名').fill(unique('Proj'));
+  await page.getByRole('button', { name: '新規プロジェクト' }).click();
+  await expect(page).toHaveURL(/\/projects\/\d+$/);
+  return Number(page.url().match(/\/projects\/(\d+)/)![1]);
+}
+
+test.describe('file sharing', () => {
+  test('upload, view in lightbox, and delete a file', async ({ page }) => {
+    const projectId = await setupOwner(page);
+
+    // アップロード(multipart)
+    const uploadRes = await page.request.post(
+      `/api/projects/${projectId}/files`,
+      {
+        multipart: {
+          file: {
+            name: 'tiny.png',
+            mimeType: 'image/png',
+            buffer: PNG_BUFFER,
+          },
+        },
+      }
+    );
+    expect(uploadRes.ok()).toBeTruthy();
+    const { file } = (await uploadRes.json()) as { file: { id: number } };
+
+    // ファイル一覧に表示
+    await page.goto(`/projects/${projectId}/files`);
+    await expect(page.getByTestId(`file-item-${file.id}`)).toBeVisible();
+
+    // 画像をクリック → Lightbox
+    await page
+      .getByTestId(`file-item-${file.id}`)
+      .getByRole('button')
+      .first()
+      .click();
+    await expect(page.getByTestId('lightbox')).toBeVisible();
+    // Lightboxを閉じる(リロードで確実に解除)
+    await page.reload();
+
+    // 削除(API)
+    const delRes = await page.request.delete(`/api/files/${file.id}`);
+    expect(delRes.ok()).toBeTruthy();
+    await page.reload();
+    await expect(page.getByTestId(`file-item-${file.id}`)).toHaveCount(0);
+  });
+});