Enhance UI and functionality: Update main page layout, add contribution options in join form, and improve member dashboard display. Refactor API endpoints for member creation and login.

app/pages/members/index.vue

@@ -6,7 +6,7 @@
         <template #title> Welcome back, {{ member?.name }}! </template>
       </UDashboardHeader>
 
-      <UGrid :cols="2" class="gap-4">
+      <div class="grid grid-cols-1 md:grid-cols-2 gap-4">
         <UCard>
           <template #header>Your Circle</template>
           <p class="text-xl font-semibold">{{ member?.circle }}</p>
@@ -25,7 +25,7 @@
             Adjust Contribution
           </UButton>
         </UCard>
-      </UGrid>
+      </div>
 
       <UCard class="mt-6">
         <template #header>Quick Links</template>