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/dashboard/page.tsx

@@ -1,5 +1,9 @@
 import { redirect } from 'next/navigation';
-import { getCurrentUser } from '@/lib/auth/getCurrentUser';
+import { getCurrentUser, toPublicUser } from '@/lib/auth/getCurrentUser';
+import { createProjectService } from '@/lib/api/services';
+import { Header } from '@/components/layout/Header';
+import { ProjectCard } from '@/components/project/ProjectCard';
+import { CreateProjectForm } from '@/components/project/CreateProjectForm';
 
 export const dynamic = 'force-dynamic';
 
@@ -9,19 +13,32 @@ export default async function DashboardPage() {
     redirect('/login');
   }
 
+  const service = createProjectService();
+  const projects = service.getMyProjects(user.id);
+
   return (
-    <main className="min-h-screen bg-gray-50 p-8">
-      <div className="mx-auto max-w-3xl">
-        <div className="flex items-center justify-between">
-          <h1 className="text-2xl font-bold">ダッシュボード</h1>
-          <a href="/profile" className="text-sm text-blue-600 hover:underline">
-            {user.name} さん
-          </a>
-        </div>
-        <p className="mt-4 text-gray-600">
-          プロジェクト機能は後続マイルストーンで実装されます。
-        </p>
-      </div>
-    </main>
+    <div className="min-h-screen bg-gray-50">
+      <Header user={toPublicUser(user)} />
+      <main className="mx-auto max-w-4xl space-y-6 p-6">
+        <h1 className="text-2xl font-bold">ダッシュボード</h1>
+        <CreateProjectForm />
+        <section>
+          <h2 className="mb-3 text-sm font-semibold text-gray-700">
+            参加プロジェクト
+          </h2>
+          {projects.length === 0 ? (
+            <p className="text-sm text-gray-400">
+              参加しているプロジェクトはありません。
+            </p>
+          ) : (
+            <div className="grid gap-3 sm:grid-cols-2">
+              {projects.map((project) => (
+                <ProjectCard key={project.id} project={project} />
+              ))}
+            </div>
+          )}
+        </section>
+      </main>
+    </div>
   );
 }