The panel was centered as a group; now the SELL grid's left edge sits at
the surface HUD's planet-text left edge (landing.hud.marginX, 24px —
same key the HUD name/line use) so the cargo grid lines up vertically
with the planet name above it, and the BUY list stretches from just
past the grid all the way to the right edge minus that same padding
(1280px window: BUY list 560 -> 770px wide; the 440px floor stays as
the narrow-window fallback). The 16px gap between the panels is
unchanged, and the sub-bar still anchors to the deck's Shop button.
shopui.json's buyList.w is now only the headless fallback width.