feat(m4): project & member management with tests and e2e

- ProjectRepository, ProjectMemberRepository, minimal NotificationRepository
- ProjectService: create/update/archive/delete project, add/remove member,
  permission checks (isMember/admin), member-added notification, getDashboard
  skeleton, getMyProjects, getMemberRole
- projectValidator, API services factory
- API routes: projects CRUD, members list/add/remove
- Screens: dashboard (project list + create form), project overview, members,
  settings; layout (Header/Sidebar/ProjectNav) and project components
- Unit tests (Project/ProjectMember repositories, ProjectService),
  integration project-member-permission, e2e project-management

app/projects/[projectId]/settings/page.tsx

@@ -0,0 +1,57 @@
+import { redirect } from 'next/navigation';
+import { getCurrentUser, toPublicUser } from '@/lib/auth/getCurrentUser';
+import { createProjectService } from '@/lib/api/services';
+import { Header } from '@/components/layout/Header';
+import { ProjectNav } from '@/components/layout/ProjectNav';
+import { ProjectSettingsForm } from '@/components/project/ProjectSettingsForm';
+import { DeleteProjectButton } from '@/components/project/DeleteProjectButton';
+import { ForbiddenError, NotFoundError } from '@/lib/errors';
+
+export const dynamic = 'force-dynamic';
+
+export default async function ProjectSettingsPage({
+  params,
+}: {
+  params: Promise<{ projectId: string }>;
+}) {
+  const user = await getCurrentUser();
+  if (!user) {
+    redirect('/login');
+  }
+  const { projectId } = await params;
+
+  const service = createProjectService();
+  let project;
+  let canManage;
+  try {
+    project = service.getProject(user.id, Number(projectId));
+    canManage = service.getMemberRole(user.id, Number(projectId)) === 'admin';
+  } catch (error) {
+    if (error instanceof ForbiddenError || error instanceof NotFoundError) {
+      redirect('/dashboard');
+    }
+    throw error;
+  }
+
+  return (
+    <div className="min-h-screen bg-gray-50">
+      <Header user={toPublicUser(user)} />
+      <ProjectNav projectId={project.id} active="settings" />
+      <main className="mx-auto max-w-2xl space-y-6 p-6">
+        <h1 className="text-2xl font-bold">プロジェクト設定</h1>
+        <div className="rounded-lg border bg-white p-6 shadow-sm">
+          <ProjectSettingsForm project={project} canManage={canManage} />
+        </div>
+        {canManage && (
+          <div className="rounded-lg border border-red-200 bg-white p-6 shadow-sm">
+            <h2 className="text-sm font-semibold text-red-700">危険操作</h2>
+            <p className="mt-1 text-sm text-gray-600">
+              プロジェクトを削除すると、関連データも削除されます。
+            </p>
+            <DeleteProjectButton projectId={project.id} />
+          </div>
+        )}
+      </main>
+    </div>
+  );
+}