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

components/ui/card.tsx

@@ -0,0 +1,46 @@
+import * as React from "react"
+import { cn } from "@/lib/utils"
+
+const Card = React.forwardRef<HTMLDivElement, React.HTMLAttributes<HTMLDivElement>>(
+  ({ className, ...props }, ref) => (
+    <div ref={ref} className={cn("rounded-lg border bg-card text-card-foreground shadow-sm", className)} {...props} />
+  )
+)
+Card.displayName = "Card"
+
+const CardHeader = React.forwardRef<HTMLDivElement, React.HTMLAttributes<HTMLDivElement>>(
+  ({ className, ...props }, ref) => (
+    <div ref={ref} className={cn("flex flex-col space-y-1.5 p-6", className)} {...props} />
+  )
+)
+CardHeader.displayName = "CardHeader"
+
+const CardTitle = React.forwardRef<HTMLParagraphElement, React.HTMLAttributes<HTMLHeadingElement>>(
+  ({ className, ...props }, ref) => (
+    <h3 ref={ref} className={cn("text-2xl font-semibold leading-none tracking-tight", className)} {...props} />
+  )
+)
+CardTitle.displayName = "CardTitle"
+
+const CardDescription = React.forwardRef<HTMLParagraphElement, React.HTMLAttributes<HTMLParagraphElement>>(
+  ({ className, ...props }, ref) => (
+    <p ref={ref} className={cn("text-sm text-muted-foreground", className)} {...props} />
+  )
+)
+CardDescription.displayName = "CardDescription"
+
+const CardContent = React.forwardRef<HTMLDivElement, React.HTMLAttributes<HTMLDivElement>>(
+  ({ className, ...props }, ref) => (
+    <div ref={ref} className={cn("p-6 pt-0", className)} {...props} />
+  )
+)
+CardContent.displayName = "CardContent"
+
+const CardFooter = React.forwardRef<HTMLDivElement, React.HTMLAttributes<HTMLDivElement>>(
+  ({ className, ...props }, ref) => (
+    <div ref={ref} className={cn("flex items-center p-6 pt-0", className)} {...props} />
+  )
+)
+CardFooter.displayName = "CardFooter"
+
+export { Card, CardHeader, CardFooter, CardTitle, CardDescription, CardContent }