Initial fullstack project setup with Next.js 15, Gin, PostgreSQL and Docker Compose

- Frontend: Next.js 15 (App Router), Auth.js v5, shadcn/ui, MagicUI
- Backend: Go + Gin + GORM with layered architecture
- Auth: Local credentials login with optional Keycloak OAuth binding
- Admin: RBAC user management for admin role
- Dev: Docker Compose with hot reload for both frontend and backend
- Docker: 3-service orchestration (frontend, backend, postgres)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/middleware.ts

@@ -0,0 +1,33 @@
+import { auth } from "@/auth";
+import { NextResponse } from "next/server";
+
+export default auth((req) => {
+  const { nextUrl } = req;
+  const isLoggedIn = !!req.auth;
+  const role = (req.auth?.user as any)?.role || "guest";
+
+  const isAuthPage = nextUrl.pathname.startsWith("/login") ||
+                     nextUrl.pathname.startsWith("/register") ||
+                     nextUrl.pathname.startsWith("/bind-account");
+
+  const isProtected = nextUrl.pathname.startsWith("/dashboard") ||
+                      nextUrl.pathname.startsWith("/admin");
+
+  if (isLoggedIn && isAuthPage) {
+    return NextResponse.redirect(new URL("/dashboard", nextUrl));
+  }
+
+  if (!isLoggedIn && isProtected) {
+    return NextResponse.redirect(new URL("/login", nextUrl));
+  }
+
+  if (nextUrl.pathname.startsWith("/admin") && role !== "admin") {
+    return NextResponse.redirect(new URL("/unauthorized", nextUrl));
+  }
+
+  return NextResponse.next();
+});
+
+export const config = {
+  matcher: ["/((?!api|_next/static|_next/image|favicon.ico).*)"],
+};