- Restored the Metal-backed `WaveformView` + `WaveformShaders.metal` + the `.process("WaveformShaders.metal")` Package.swift rule so the default.metallib lands in the module bundle. Reads as a small 56pt visualizer strip below the staff bezel rather than the full-block visualizer the rc1 reshape retired. - Added `HoverTrackingView` as a standalone reusable class (was inline in Esteban's mirror copy of MenuBandPopover). - Predictive metronome beat bars: derived in StaffView.draw from `KeyboardIconRenderer.metronomeBPM` + `metronomeStartTime`. Each upcoming click materializes at `clickTime − traverseTime` on the RIGHT edge and slides leftward to the play column. While approaching the bar paints as a faint ghost; on arrival at the centerline it pops yellow for ~3 frames (the "slot in" cue), then settles to the resting metronome-trail tone as it scrolls off. Removes the imperative `dropBeatMarker` callback from the popover's onTick — bars are now derived from time, not pushed. - Staff bezel extends to the popover stack's full width (`preferredWidth + 16`) so the rolling lines + accent sharp guides + ghost ledger lines paint edge-to-edge instead of being inset to the chooser-row's interior margin. - `QwertyLayoutView.acceptsFirstMouse(for:)` returns true so the floating piano panel doesn't swallow the first mouseDown that activates it, restoring click-and-drag-across-keys behavior when the user starts on the QWERTY map after another window had focus. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>