Enhance video playback cubit resilience and K-12 curriculum flow

apps/student_app/lib/presentation/widgets/luxury_widgets.dart

@@ -120,15 +120,17 @@ class LuxuryTextField extends StatelessWidget {
   final TextInputType keyboardType;
   final Widget? prefixIcon;
   final bool enabled;
+  final ValueChanged<String>? onChanged;
 
   const LuxuryTextField({
     super.key,
     required this.controller,
-    required this.label,
+    this.label = '',
     required this.hint,
     this.keyboardType = TextInputType.text,
     this.prefixIcon,
     this.enabled = true,
+    this.onChanged,
   });
 
   @override
@@ -136,18 +138,21 @@ class LuxuryTextField extends StatelessWidget {
     return Column(
       crossAxisAlignment: CrossAxisAlignment.start,
       children: [
-        Text(
-          label,
-          style: AppTypography.titleMedium.copyWith(
-            color: AppColors.textSecondaryDark,
-            fontSize: 13,
+        if (label.isNotEmpty) ...[
+          Text(
+            label,
+            style: AppTypography.titleMedium.copyWith(
+              color: AppColors.textSecondaryDark,
+              fontSize: 13,
+            ),
           ),
-        ),
-        const SizedBox(height: 8),
+          const SizedBox(height: 8),
+        ],
         TextField(
           controller: controller,
           keyboardType: keyboardType,
           enabled: enabled,
+          onChanged: onChanged,
           style: AppTypography.bodyMedium.copyWith(
             color: Colors.white,
             fontSize: 15,