Parse each RATC bundle's .rat layout records (sprite name @0x20, placement
block [scale,tint,X,Y]) and composite the .t32 sprites back into the screen
image. Validated: GP_PAUSE_MENU rebuilds pixel-accurately (btn X=226,
Y=268/337/407/478 — the documented 70px pitch); focus records land 42px
left/8px up. Compositor confirmed by rendering the pause menu from disc alone.
Format doc: docs/re/structures/ui-rat-layout.md (agent RE).
