Though the construction is not yet completed, 49ers fans are flocking to Levi's Stadium to announce their good news.Last month, a man proposed to his girlfriend, marking the first marriage proposal at the new home of the San Francisco 49ers.And last week, Harjeet Janda and her husband, Kevin Janda, both 28 and San Jose residents, used the stadium as a backdrop to announce the birth of their son.The happy, high-tech couple (he works at Facebook, she works at Apple) donned yellow construction vests, and held up a small chalkboard announcing their due date on Aug. 29. They know they're having a boy, which is why they brought along a football decked out in a mustache. - 49ers Fan Proposes to Girlfriend at Levi's StadiumWhile they had told their friends and family that Harjeet Janda is pregnant, she said they hadn't gone "Facebook official" with the news, which is why they staged the shot."We did it on a whim," she said. "We're die-hard 49er fans."They wanted to have the announcement splashed across the stadium's video board, like Scott Onick got to in late April when he proposed to his girlfriend, Sarah Cookson, at the stadium.But Janda said she was told...