[Feature] Support Multiple Accounts and Quick Account Switching

I have searched the existing feature requests, both open and closed, to make sure this is not a duplicate request. • Yes The feature Description I would like to request the ability to add and save multiple accounts in Immich and quickly switch between them without having to log out and log back in every time. The idea is to introduce a “Switch Account” option that allows users to add multiple Immich accounts, keep them saved, and switch between them whenever needed. Related discussions: #4718 — Sign in to Multiple Accounts on Mobile App (Account Switching) #7700 — Mobile Multi Server Switching #2919 — Multi-account/profile switching support This feature request builds on the existing discussions and highlights the need for a convenient, persistent account switcher that allows users to save multiple accounts and switch between them without logging out and signing in again. Proposed Behavior • Allow users to add and save multiple Immich acco…