fix: Add row/col/tier to mock 3D data so Racks actually render

frontend/src/components/facility3d/Room3DViewer.tsx

@@ -41,11 +41,21 @@ export function Room3DViewer({ room, visMode = 'STANDARD', onPlantClick }: Room3
             posY: 10,           // Centered Y roughly
             width: 4,
             height: 20,
-            positions: Array.from({ length: 16 }).map((__, p) => ({
+            positions: Array.from({ length: 16 }).map((__, p) => {
+                const tier = Math.floor(p / 4);
+                const remainder = p % 4;
+                const row = Math.floor(remainder / 2);
+                const column = remainder % 2;
+                return {
                     id: `p-${i}-${p}`,
                     name: `P${p + 1}`,
-                valid: true
+                    valid: true,
-            }))
+                    tier,
+                    row,
+                    column,
+                    sectionId: `mock-rack-${i}` // Adding sectionId for completeness if needed
+                };
+            })
         }));
 
         return {