The exasperation runs both ways. Interviews with nearly three dozen former and current Harris aides, administration officials, Democratic operatives, donors and outside advisers — who spoke extensively to CNN — reveal a complex reality inside the White House. Many in the vice president’s circle fume that she’s not being adequately prepared or positioned, and instead is being sidelined. The vice president herself has told several confidants she feels constrained in what she’s able to do politically. And those around her remain wary of even hinting at future political ambitions, with…