PHILADELPHIA — The Philadelphia Police Department and city officials “were simply not prepared” for large-scale protests this summer after George Floyd was killed by Minneapolis police, leaving police short-staffed, lacking equipment, and without a suitable plan to respond to demonstrations that quickly grew in size and intensity and lasted several days, according to a review commissioned by Mayor Jim Kenney. As a result, the review found, the Police Department’s initial planning mistakes had “cascading effects” as demonstrations spilled into areas including West Philadelphia and I-676, includ…