Interface MeterLevel

MAIN_C's own peak, 0..1 (#176) — present ONLY on MAIN when its bus is lcr. A THIRD bar, never a substitute for right (an lcr main still carries L/R too).

LIVE gain reduction (dB, ≤ 0; 0 = no reduction) the channel's built-in GATE / COMP dynamics slot applied, when the adapter's meter source measures it — see @freemixer/audio-engine's NativeMeterSource. This is the TRUE DSP-applied reduction (post attack/release envelope), not a UI-side estimate off the static curve shape. Omitted on a path that doesn't measure it (the loopback path); the Gate/Comp transfer-curve widgets fall back to their local estimate in that case.