fix(ux): retry scroll with requestAnimationFrame until DOM ready

Replaces fixed 300ms setTimeout with rAF loop that retries
until #treinos-pessoais anchor exists in DOM. Eliminates
race condition on slow devices / slow RSC renders.

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

Author: EmiyaKiritsugu3

src/app/aluno/meus-treinos/meus-treinos-client.tsx

@@ -63,11 +63,15 @@ export default function MeusTreinosClient({
     notify,
     onSuccess: () => {
       router.refresh();
-      setTimeout(() => {
-        document
-          .getElementById('treinos-pessoais')
-          ?.scrollIntoView({ behavior: 'smooth', block: 'start' });
-      }, 300);
+      const scrollToTreinos = () => {
+        const el = document.getElementById('treinos-pessoais');
+        if (el) {
+          el.scrollIntoView({ behavior: 'smooth', block: 'start' });
+          return;
+        }
+        requestAnimationFrame(scrollToTreinos);
+      };
+      requestAnimationFrame(scrollToTreinos);
     },
   });