- Transport: play/stop/back/next/record buttons in piano roll toolbar
- ARM toggle + MIDI input device selector next to Snap to Scale
- AI bar range selector (bar X to bar Y) for Copilot MIDI generation
- handleAISend detects active piano roll tab and routes MIDI prompt
- Added selectedMidiInputId state + handleMidiInputSelect for MIDI input
- PADDING_LEFT=0 in all 3 components (grid aligns with clip origin)
- TempoTrackLane/WaveformLane tEnd uses CLIP_BUFFER/zoom so bars render past right edge
- TimelineRuler tEnd uses CLIP_BUFFER/zoom instead of PADDING_LEFT
- Removed Math.max(beatSec, ...) clamp from clip drag, section drag, section resize handlers
- Replaced with Math.max(0, ...) so items can snap to time 0
- leadInMargin=0, time 0 at left edge, only 8px PADDING_LEFT
- TimelineRuler simplified: time-only labels, 40px height
- TempoTrackLane re-added to layout below time ruler (40px)
- WaveformLane PADDING_LEFT=8/zoom, leadIn=0
- Added leadInMargin prop to TempoTrackLane so time-0 aligns with ruler
- Added CLIP_BUFFER to TempoTrackLane grid rendering
- Moved TimelineRuler time labels from bottom (y=40) to top (y=11)
- Add 1-bar lead-in margin at timeline start (bar 0, time 0s at margin edge)
- Playhead position includes lead-in offset
- Bar numbers now 0-indexed (0, 1, 2...) in ruler and track grid
- Fix bar number clipping: CLIP_BUFFER increased from 200px to
max(400px, barWidth+200px) so bars past viewport edge render
- All mouse/time handlers account for lead-in margin (ruler, clip
drag, section drag/resize, context menu, double-click)
- formatBeat returns 0-indexed bar
- Sub-tab ruler has leadInMargin=0 (no lead-in in clip editor)
3dtours