v1.45.0

Beat opener: the hit lands on the beat, and the waveform zooms (v1.45.0)

The owner's kick drum played a few frames after the screen cut to black:
their window began in the quiet before the kick, playback starts at the
window's edge, and a mouse can't land that edge on the exact sample.
Measured 150 ms late on every cut. The app now finds the hit inside the
chosen part (where it goes from quiet to loud) and plays from there, so
the kick lands 1.2 ms after each cut - a deliberate 1 ms lead-in. A part
that is already sounding at its start, like a pad, is never moved. The
status says where the hit was found and a marker shows it on the waveform.

A long sound was "very very hard to select a small portion" from, so the
waveform now zooms (1x-32x, slider or scroll over it), with an overview
strip to move around, a 1x button to zoom back out, and real detail when
zoomed. 636 smoke checks, golden passes; render/ is unchanged. The PLAY
preview's audio was checked by its state, not by ear.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>