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

app/providers.tsx

@@ -0,0 +1,6 @@
+'use client'
+import { SessionProvider } from 'next-auth/react'
+
+export function Providers({ children }: { children: React.ReactNode }) {
+  return <SessionProvider>{children}</SessionProvider>
+}