feat(backend): Phase 0 项目骨架完成 — 后端/前端/数据库/Docker

- 后端：FastAPI + SQLAlchemy + Alembic，7 张核心表迁移成功
- 前端：Next.js 16 + TailwindCSS 4 + 三端布局（投资人/创始人/Admin）
- 数据库：PostgreSQL 16，7 张核心实体表（tenants/users/companies/monthly_reports/health_scores/risk_events/audit_logs）
- Docker：docker-compose.yml + 前后端 Dockerfile
- 测试：健康检查 4 个测试全部 GREEN
- 文档：README/run.md/AGENTS.md/docs 体系完整

frontend/src/app/(investor)/dashboard/page.tsx

@@ -0,0 +1,15 @@
+/** 投资人端驾驶舱首页 — 占位页面。 */
+
+import { LoadingSpinner } from "@/components/shared/LoadingSpinner";
+
+export default function InvestorHomePage() {
+  return (
+    <div className="space-y-6">
+      <div>
+        <h1 className="text-2xl font-bold text-foreground">投资机构驾驶舱</h1>
+        <p className="mt-1 text-sm text-muted-foreground">Portfolio 全局健康度与风险概览</p>
+      </div>
+      <LoadingSpinner className="py-20" size={32} />
+    </div>
+  );
+}

frontend/src/app/(investor)/layout.tsx

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+/** 投资人端布局 — B 端专业风格：左 Sidebar + 灰色内容区。 */
+
+import { LayoutDashboard, Building2, FileText, AlertTriangle, Settings } from "lucide-react";
+import Link from "next/link";
+
+const navItems = [
+  { href: "/dashboard", label: "驾驶舱", icon: LayoutDashboard },
+  { href: "/companies", label: "企业档案", icon: Building2 },
+  { href: "/reports", label: "月报管理", icon: FileText },
+  { href: "/risks", label: "风险工作台", icon: AlertTriangle },
+  { href: "/settings", label: "设置", icon: Settings },
+];
+
+export default function InvestorLayout({ children }: { children: React.ReactNode }) {
+  return (
+    <div className="flex min-h-screen">
+      {/* 左侧 Sidebar */}
+      <aside className="sticky top-0 hidden h-screen w-52 shrink-0 bg-[var(--investor-sidebar-bg)] text-white md:block">
+        <div className="flex h-14 items-center px-4 font-bold">AIPortPilot</div>
+        <nav className="flex flex-col gap-1 px-3 py-2">
+          {navItems.map((item) => (
+            <Link
+              key={item.href}
+              href={item.href}
+              className="flex items-center gap-2 rounded-md px-3 py-2 text-sm text-white/70 transition-colors hover:bg-white/10 hover:text-white"
+            >
+              <item.icon size={16} aria-hidden="true" />
+              {item.label}
+            </Link>
+          ))}
+        </nav>
+      </aside>
+
+      {/* 内容区 */}
+      <main className="flex-1 bg-[var(--investor-content-bg)]">
+        {/* 移动端顶部 Header */}
+        <header className="sticky top-0 z-10 flex h-14 items-center bg-[var(--investor-sidebar-bg)] px-4 text-white md:hidden">
+          <span className="font-bold">AIPortPilot</span>
+        </header>
+        <div className="container mx-auto max-w-7xl px-4 py-6">{children}</div>
+      </main>
+    </div>
+  );
+}