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

lib/utils.ts

@@ -0,0 +1,32 @@
+import { type ClassValue, clsx } from 'clsx'
+import { twMerge } from 'tailwind-merge'
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs))
+}
+
+export function generateApiKey(): string {
+  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
+  let result = 'nfc_'
+  for (let i = 0; i < 32; i++) {
+    result += chars.charAt(Math.floor(Math.random() * chars.length))
+  }
+  return result
+}
+
+export function slugify(text: string): string {
+  return text
+    .toLowerCase()
+    .replace(/[^a-z0-9]+/g, '-')
+    .replace(/(^-|-$)/g, '')
+}
+
+export function formatPhone(phone: string): string {
+  const cleaned = phone.replace(/\D/g, '')
+  if (cleaned.startsWith('0') && cleaned.length === 11) {
+    return '63' + cleaned.slice(1)
+  }
+  if (cleaned.startsWith('63') && cleaned.length === 12) return cleaned
+  if (cleaned.length === 10) return '63' + cleaned
+  return cleaned
+}