feat: initial NFC Attendance Hub implementation

- Multi-tenant client management with unique API keys
- Semaphore SMS integration (per-client key + sender name + credit balance)
- DB-based SMS queue with 3-attempt retry and exponential backoff
- Failed SMS dashboard with manual retry button
- Reports page with date/client filter and CSV export
- Admin auth via NextAuth (email/password)
- Docker Compose setup (app + PostgreSQL 16)
- Prisma 5 schema with SmsQueue, SmsLog, Client, User models

Tech: Next.js 14 App Router + TypeScript + Tailwind CSS + Prisma + PostgreSQL

next.config.mjs

@@ -0,0 +1,9 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {
+  output: 'standalone',
+  experimental: {
+    serverComponentsExternalPackages: ['@prisma/client', 'bcryptjs'],
+  },
+};
+
+export default nextConfig;