v0.7.2

Fixed

• fps source no longer writes --live-fps every frame. The exponential
  moving average is still sampled per frame, but the value is now written at most
  every 250 ms (≤4 Hz). Writing per frame coupled the readout to the frame rate:
  each write invalidates --live-fps for the whole tree, and on a large reactive
  DOM that restyle is heavy enough to lower the frame rate, which changes the
  rounded value, which writes again — a feedback loop that spiralled FPS downward
  and accumulated restyle/GC work in Firefox until the tab hung and crashed (no
  user interaction required). The throttled write breaks the loop; an fps readout
  doesn't need to update faster than a few hertz anyway. Values are unchanged
  (rounded EMA), only the write cadence is bounded.