Player-telemetry QoE parser

A dependency-free (pure standard-library) Python tool that performs the exact derivation an analytics SDK does on the device: it reads a raw player-event log (loadstart/play, playing, waiting, seeking/seeked, rendition <kbps>, error, ended) and reconstructs the standard player-side QoE metrics. STARTUP = play intent → first 'playing'. REBUFFERING = each 'waiting'→'playing' pair NOT bracketed by a seek (seek waits are excluded), reported as count, total duration, and TWO ratio conventions (stall/