Fix: setupModes ne cible que les boutons de l'ecran mode (pas admin)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/js/app.js

@@ -174,7 +174,7 @@ document.addEventListener('keydown', (e) => {
 // --- Modes ---
 
 function setupModes() {
-  document.querySelectorAll('.btn-mode').forEach(btn => {
+  document.querySelectorAll('#ecran-mode .btn-mode').forEach(btn => {
     btn.addEventListener('click', () => {
       modeActuel = btn.dataset.mode;
       allerA('capture');