fix: JSX structure in credit.tsx

- Fix nested tag structure: AI Credits tab was incorrectly nested inside Platform Ledger section
- Close Platform Ledger section before starting AI Credits tab
- Move AI Credits tab to be a sibling of Platform Ledger tab, not a child
- Wrap AI Credits content in proper section element for consistent styling

src/routes/admin/credit.tsx

@@ -620,9 +620,12 @@ export default function CreditPage() {
           >
             <LedgerSection entries={platformLedger() ?? []} showUser onExport={undefined} />
           </Show>
+        </section>
+      </Show>
 
       {/* AI Credits Tab */}
       <Show when={activeTab() === 'ai_credits'}>
+        <section class="rounded-xl border border-gray-200 bg-white shadow-sm" style="margin-top:1.5rem">
           <div>
               {/* AI Credits Sub-tabs */}
               <div class="bg-white border-b border-gray-200 px-0 flex items-center gap-6 mb-6">
@@ -921,7 +924,8 @@ export default function CreditPage() {
               </Show>
             </div>
           </Show>
-        </div>
+        </section>
+      </Show>
     </div>
   );
 }