StaffView: - Beat-snap: a note pressed within 130ms of the most recent beat marker anchors `appearedAt` to that beat's `capturedAt` instead of "now" so the leading pill edge lines up exactly with the metronome bar (compensates for typical ~50–120ms reaction-time latency). - Perfect-hit reward: presses within a tighter 60ms window log a PerfectHit for the held note's staff line. The line's stroke blends toward white over 180ms before settling back to its base color — small "you nailed it" UI cue. InstrumentMapView: - Cells now paint `windowBackgroundColor` first then a 55%-alpha family-color overlay (selected: 95%), so the chiclets read as an opaque grid instead of letting the popover's glass bleed through every cell. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>