Refactor: Fix silent failure in name validation

Updated `OnboardingViewModel.saveName` to return a `Boolean` indicating success.
Updated `OnboardingScreen` to check this return value and show a Toast message if validation fails, preventing navigation to the next step.
This addresses the feedback that the previous refactoring allowed users to proceed with a blank name.

Author: google-labs-jules[bot]

app/src/main/java/com/example/theloop/OnboardingViewModel.kt

@@ -22,12 +22,14 @@ class OnboardingViewModel @Inject constructor(
         _name.value = newName
     }
 
-    fun saveName() {
+    fun saveName(): Boolean {
         if (name.value.isNotBlank()) {
             viewModelScope.launch {
                 userPreferencesRepository.saveUserName(name.value)
             }
+            return true
         }
+        return false
     }
 
     fun completeOnboarding() {

app/src/main/java/com/example/theloop/ui/screens/OnboardingScreen.kt

@@ -98,7 +98,10 @@ fun OnboardingScreen(
                     Button(onClick = {
                         if (currentStep == 0) {
                             // Save Name
-                            viewModel.saveName()
+                            if (!viewModel.saveName()) {
+                                Toast.makeText(context, "Name cannot be blank", Toast.LENGTH_SHORT).show()
+                                return@Button
+                            }
                         }
 
                         if (currentStep < totalSteps - 1) {