AsyncAO v1.96.2

Hotfix for the animation swap stutter: a progressive first-frame "Partial"
delivery was being treated as the real animation, which froze a swapping
sprite on one static frame and could cut a preanimation short.

• Fixed a frame of frozen/blank sprite when animations swap — the fast
  one-frame partial (the "show frame 0 while the clip decodes" path) no longer
  displaces the hold-previous sprite during a swap, so the previous animation
  keeps playing until the full clip lands instead of freezing on a single
  static frame for the rest of the decode. The partial is still used on a cold
  load (no previous sprite to hold), so first-frame latency is unchanged.
• Fixed preanimations ending after one frame — a one-shot (pre)animation no
  longer reports itself finished on that one-frame partial, so preanims (e.g.
  Ridelle's bow/damage lead-ins) play to their natural last frame instead of
  being cut short the instant their first frame decoded.