Function profiles_unlock 

pub async fn profiles_unlock(
    app: AppHandle,
    db: State<'_, DatabaseWrapper>,
    creds: State<'_, CredentialStoreWrapper>,
    auth_manager: State<'_, AuthManagerWrapper>,
    repository_manager: State<'_, RepositoryManagerWrapper>,
    session_poller: State<'_, SessionPollerWrapper>,
    user_id: String,
    pin_code: Option<String>,
) -> Result<UnlockOutcome, String>

Enter a profile, with its PIN if it has one.

A profile with no PIN ignores whatever pin was passed — the frontend cannot invent a lock the backend does not have, and cannot skip one it does.

TRACES: UR-082, UR-083 | DR-267, DR-268, DR-270