Case Insensitive Logins

This module changes how Odoo handles user login names so that capitalisation no longer matters. When someone signs in, the login they type is converted to lowercase before being checked, so "John.Smith" and "john.smith" are treated as the same account.

It also keeps logins consistent going forward: - When a new user is created, the login is automatically stored in lowercase. - When an existing user's login is changed, the new value is stored in lowercase too.

Because older databases may already contain logins with capital letters, the module includes two installation steps. Before installation it checks all existing logins and stops the installation with a clear error if two accounts would become identical once lowercased, preventing duplicate accounts. After installation it converts every existing login to lowercase.

The module works on the res.users model, which is the model behind user accounts and the login screen. It depends on the mail module. No new menus, screens, buttons or reports are added; the change is invisible in daily use apart from the fact that users no longer need to remember the exact capitalisation of their login.