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/api/clients/route.ts

@@ -0,0 +1,37 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { getServerSession } from 'next-auth'
+import { authOptions } from '@/lib/auth'
+import { prisma } from '@/lib/prisma'
+import { generateApiKey, slugify } from '@/lib/utils'
+
+export async function GET() {
+  const session = await getServerSession(authOptions)
+  if (!session) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const clients = await prisma.client.findMany({
+    orderBy: { createdAt: 'desc' },
+    include: {
+      _count: { select: { smsQueue: true, smsLogs: true } },
+    },
+  })
+  return NextResponse.json(clients)
+}
+
+export async function POST(req: NextRequest) {
+  const session = await getServerSession(authOptions)
+  if (!session) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const body = await req.json()
+  const { name, semaphoreKey, senderName } = body
+
+  if (!name) return NextResponse.json({ error: 'Name is required' }, { status: 400 })
+
+  const slug = slugify(name)
+  const apiKey = generateApiKey()
+
+  const client = await prisma.client.create({
+    data: { name, slug, apiKey, semaphoreKey, senderName: senderName || 'NFC-HUB' },
+  })
+
+  return NextResponse.json(client, { status: 201 })
+}