Rep. Tom Kean Jr. (R-N.J.) plans to end his months-long absence and return to Capitol Hill at the end of the month, a spokesperson said Thursday.Why it matters: The mysterious nature of Kean's more than 100-day disappearance has captured national attention, especially as he is running for re-election in a hotly contested battleground district.Kean said in a statement in April that he was dealing with a "personal medical issue," but he and his staff have thus far declined to offer further details...