feat: add display name functionality for users and update related views

src/middleware/auth.js

@@ -36,6 +36,7 @@ function loadUser(req, res, next) {
     res.locals.currentUser = {
       id: req.session.userId,
       username: req.session.username,
+      displayName: req.session.displayName || req.session.username,
       isAdmin: req.session.isAdmin,
       isOrganizer: req.session.isOrganizer
     };