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.

routes/version.js

@@ -79,7 +79,8 @@ router.get("/", async (req, res) => {
     if (!active) {
       return res.status(200).json({
         version: getPackageVersion(),
-        message: "Version non configurée (définis-la dans Admin → Version).",
+        messageKey: 'footer.versionNotConfigured',
+        message: 'Version not configured (set it in Admin → Version).',
         author: "",
         date: nowFormatted(),
         configured: false,
@@ -103,7 +104,8 @@ router.get("/", async (req, res) => {
     // If DB is down, still return something useful.
     return res.status(200).json({
       version: getPackageVersion(),
-      message: "Version indisponible (DB).",
+      messageKey: 'footer.versionUnavailable',
+      message: 'Version unavailable (DB).',
       author: "",
       date: nowFormatted(),
       configured: false,