feat: initial commit — backend API + student cabinet frontend

- Go backend: auth (JWT), points earn/spend, QR token generation,
  partners, admin grant/stats endpoints with chi router
- Next.js 14 frontend: login, student dashboard, transaction history,
  QR display, partners list
- PostgreSQL migrations (4 tables), Redis cache, Docker Compose
- CORS middleware, role-based route protection, Zustand auth store

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/components/ui/Input.tsx

@@ -0,0 +1,23 @@
+import { type InputHTMLAttributes, useId } from 'react';
+
+interface InputProps extends InputHTMLAttributes<HTMLInputElement> {
+  label: string;
+  error?: string;
+}
+
+export function Input({ label, error, className = '', ...props }: InputProps) {
+  const id = useId();
+  return (
+    <div className="flex flex-col gap-1">
+      <label htmlFor={id} className="text-sm font-medium text-gray-300">
+        {label}
+      </label>
+      <input
+        id={id}
+        className={`rounded-lg border bg-gray-700 px-3 py-2 text-sm text-white placeholder-gray-500 outline-none transition-colors focus:ring-2 ${error ? 'border-red-500 focus:border-red-500 focus:ring-red-800' : 'border-gray-600 focus:border-blue-500 focus:ring-blue-900'} ${className}`}
+        {...props}
+      />
+      {error && <p className="text-xs text-red-400">{error}</p>}
+    </div>
+  );
+}