Implement en/fr localization across admin and user UIs

Introduce client-side localization helper and en/fr locale bundles.

Route admin control, picks, movies, stats, winners and settings UIs through i18n keys instead of hardcoded text.

Remove French text from the English UI and standardize shared messages (saving, network errors, confirmations).

Update .gitignore to ignore editor metadata and localization helper artifacts.

public/js/app_change-password.js

@@ -2,6 +2,20 @@ function decodeJwt(token) {
   return JSON.parse(atob(token.split('.')[1]));
 }
 
+// i18n helper function
+function t(key, fallback = '', params = {}) {
+  if (window.i18n && typeof window.i18n.t === 'function') {
+    return window.i18n.t(key, params);
+  }
+  let result = fallback;
+  if (params && typeof params === 'object') {
+    Object.keys(params).forEach(k => {
+      result = result.replace(`{${k}}`, String(params[k]));
+    });
+  }
+  return result;
+}
+
 function isTokenExpired(decoded) {
   const currentTime = Math.floor(Date.now() / 1000);
   return !!decoded.exp && decoded.exp < currentTime;
@@ -81,11 +95,11 @@ window.onload = function () {
     const confirmPassword = document.getElementById('confirm-password').value;
 
     if (newPassword.length < 8) {
-      showError('Le mot de passe doit contenir au moins 8 caractères.');
+      showError(t('auth.passwordMinLength', 'Password must be at least 8 characters.'));
       return;
     }
     if (newPassword !== confirmPassword) {
-      showError('Les mots de passe ne correspondent pas.');
+      showError(t('auth.passwordsDoNotMatch', 'Passwords do not match'));
       return;
     }
 
@@ -116,7 +130,7 @@ window.onload = function () {
 
       window.location.href = '/movies.html';
     } catch (err) {
-      showError(err.message || 'Erreur réseau');
+      showError(err.message || t('auth.networkError', 'Network error'));
     }
   });
 };