SAN FRANCISCO (Reuters) - California's attorney general predicted on Monday that the courts would bar same-sex marriages in San Francisco within weeks and invalidate the thousands of gay marriages the city has sanctioned over the past two weeks. "I think it will be weeks and my best prediction is that the marriages will be invalidated, the courts will direct people that wish to change the law to the legislative process," Bill Lockyer, the Democratic attorney general, told Reuters in a telephone interview. Over the past 10 days, San Francisco has issued marriage licenses to 3,175 homosexual couples, prompting euphoria in...