* fix: data-volume multiplies the volume lane in preview and render
* fix: a clip's data-volume plays ahead of its audio effects, in preview and render
* feat(studio): the media panel shows a clip's Gain beside its Volume level
* fix(audio): cap gain times volume lanes through each ramp
* chore(core): account for shared volume envelopes in package budget
* fix(core): restore static gain when a playing lane is removed