The previous "fix" for Scale's crop bias paired Scale with a computed
Translate, on the mistaken assumption that Scale's default pivot is the
top-left corner. It isn't: pixlet's docs say the default origin is
already the center (0.5, 0.5). That Translate was sized assuming Scale
had no self-centering at all, so it overcorrected, visibly skewing the
zoom toward the bottom-right -- the opposite of the bug it meant to fix.
animation.Origin does directly and correctly what that Translate was
clumsily approximating, so the Translate (and its rounding="none"
workaround) is removed entirely in favor of Origin. This also means
"strong" no longer needs the 1.45 safety cap -- restored to 1.7, since
the black-border risk was specific to the Translate formula, not Scale +
Origin (verified via the calibration tool at several off-center origins).
Added a "Zoom position" schema option: Center (default) or Random. Random
picks from a handful of preset off-center spots, chosen per-track from
subsonic_id the same way the old corner-selection logic worked, so a
still-playing track doesn't jump between spots on every refresh.
Verified: no black border, no popping (confirmed via frame-delta
analysis -- smooth throughout, no Translate means rounding is moot), and
payload well under the 460KB limit at every zoom level/position
combination, against the live station.