James Harden’s days in Philadelphia are unofficially over, with the Sixers star deciding on Thursday to opt into the $35.6 million option on his contract for next season en route to asking for a trade, as The Athletic’s Shams Charania first reported. According to sources directly involved in the situation on both sides, the Los Angeles native wants to play for the Clippers and the Sixers are already in the process of discussing his desired move. Harden is, according to sources close to him, extremely upset at the way in which the Sixers handled his possible free agency and has…