- The dock now sits in the preview column (Grid.Column=1), so its left edge is the layers panel's
right edge instead of starting under the brand column. It is a preview-column control, not a
full-width footer.
- Expanded height 168 → 148 (112 bays + 36 master strip): the mockup's number read as wasted space
beneath the 154px scene strip.
Guard: AudioDockLayoutTests pins 148 as the design number, so the constant cannot drift silently.