A record 401,900 Hongkongers have signed up to vote in the past year following a campaign by opposition politicians, who are aiming to win more than half the seats being contested in September’s Legislative Council elections.The surge means there are more than 4.45 million registered voters in Hong Kong, according to the Registration and Electoral Office, which released its provisional register on Monday.The office arrived at the new tally, which represents a net increase of 322,400, after…