Add the cockpit glass-sizing declarations missed by the last commit

L4VB16.h carries GlassSize and CockpitGlassSizes, which L4VB16.cpp uses
in both the constructor and LayoutCockpit - 8dc6605 left it behind (the
add named the path in the wrong case), so that commit does not build on
its own.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

MUNGA_L4/L4VB16.h

@@ -308,6 +308,26 @@ private:
 		SplitViewCount
 	};
 
+public:
+	//------------------------------------------------------------------
+	// Glass size of one secondary display, in whatever units the caller
+	// asked for (canvas units while clamping, device pixels on return).
+	//------------------------------------------------------------------
+	struct GlassSize
+	{
+		int w, h;
+	};
+
+protected:
+	//------------------------------------------------------------------
+	// The six displays sized for a given canvas scale, honouring the
+	// player's per-display scaling and clamped to keep the pod
+	// arrangement legal. Every layout goes through here, first and
+	// resized alike, so the two can never disagree.
+	//------------------------------------------------------------------
+	static void
+		CockpitGlassSizes(int scale, GlassSize sizes[SplitViewCount]);
+
 	void
 		FillSplitMFD(
 			SplitViewID view,