feat: implementasi Kodeva - sistem manajemen kursus coding

Fitur lengkap:
- Auth JWT + RBAC (Admin/Teacher) + halaman login
- Shell 3 kolom (left nav, topbar, right rail dashboard)
- CRUD siswa + follow up kanban + status calon/student/ex
- Dashboard: siswa aktif, kehadiran, bar sumber lead, perlu follow up
- Pembayaran prorata per pertemuan (cash/transfer/qris)
- Kelas, enrollment, generate sesi, kehadiran bulk
- Jurnal aktivitas + upload multi-foto
- Raport + placement test (tampil di detail siswa)
- Pengaturan & seed data contoh

Stack: Next.js 16, TypeScript, Tailwind v4, Prisma (SQLite), Recharts, Zod

src/app/login/actions.ts

@@ -0,0 +1,35 @@
+"use server";
+
+import { redirect } from "next/navigation";
+import bcrypt from "bcryptjs";
+import { prisma } from "@/lib/prisma";
+import { loginSchema } from "@/lib/validators";
+import { clearSessionCookie, setSessionCookie } from "@/lib/auth";
+
+export type LoginState = { error?: string } | undefined;
+
+export async function loginAction(_prev: LoginState, formData: FormData): Promise<LoginState> {
+  const parsed = loginSchema.safeParse({
+    email: formData.get("email"),
+    password: formData.get("password"),
+  });
+  if (!parsed.success) return { error: "Email atau password tidak valid." };
+
+  const user = await prisma.user.findUnique({ where: { email: parsed.data.email } });
+  if (!user || !user.isActive || !bcrypt.compareSync(parsed.data.password, user.passwordHash)) {
+    return { error: "Email atau password salah." };
+  }
+
+  await setSessionCookie({
+    userId: user.id,
+    name: user.name,
+    email: user.email,
+    role: user.role === "ADMIN" ? "ADMIN" : "TEACHER",
+  });
+  redirect("/dashboard");
+}
+
+export async function logoutAction() {
+  await clearSessionCookie();
+  redirect("/login");
+}