CLAUDE: Save NADIR-DISPARITY-MAPS hyperstack from getNadirDisparityMaps()

After computing per-scene pXpYD arrays, saves a tile-resolution
hyperstack <ts>-NADIR-DISPARITY-MAPS.tiff with:
  - frames = scenes (labelled by timestamp)
  - slices = pX, pY, D (3 channels)
  - NaN where scene has no pose or tile has no data

Useful for verifying disparity transform coverage before feeding
the rendered images into OpenMVS/COLMAP.
Co-authored-by: Claude <claude@elphel.com>

src/main/java/com/elphel/imagej/tileprocessor/OpticalFlow.java

@@ -10877,6 +10877,40 @@ java.lang.NullPointerException
     				num_virtual_refines, // final int       num_refines,
     				null);               // final String    debugSuffix
     	}
+    	// Save pX/pY/D hyperstack for each scene at tile resolution
+    	int tilesX = ref_scene.getTilesX();
+    	int tilesY = ref_scene.getTilesY();
+    	int ntiles = tilesX * tilesY;
+    	String [] slice_titles  = {"pX", "pY", "D"};
+    	String [] frame_titles  = new String[selected_scenes.length];
+    	double [][][] disp_maps = new double[selected_scenes.length][3][ntiles];
+    	for (int ns = 0; ns < selected_scenes.length; ns++) {
+    		frame_titles[ns] = selected_scenes[ns].getImageName();
+    		Arrays.fill(disp_maps[ns][0], Double.NaN);
+    		Arrays.fill(disp_maps[ns][1], Double.NaN);
+    		Arrays.fill(disp_maps[ns][2], Double.NaN);
+    		if (nadir_pXpYD[ns] != null) {
+    			for (int t = 0; t < ntiles; t++) {
+    				if (nadir_pXpYD[ns][t] != null) {
+    					disp_maps[ns][0][t] = nadir_pXpYD[ns][t][0]; // pX
+    					disp_maps[ns][1][t] = nadir_pXpYD[ns][t][1]; // pY
+    					disp_maps[ns][2][t] = nadir_pXpYD[ns][t][2]; // D (disparity)
+    				}
+    			}
+    		}
+    	}
+    	ImagePlus imp_disp_maps = ShowDoubleFloatArrays.showArraysHyperstack(
+    			disp_maps,                                              // double [][][]  pixels,
+    			tilesX,                                                 // int            width,
+    			ref_scene.getImageName() + "-NADIR-DISPARITY-MAPS",    // String         title,
+    			slice_titles,                                           // String []      titles,
+    			frame_titles,                                           // String []      frame_titles,
+    			false);                                                 // boolean        show
+    	if (imp_disp_maps != null) {
+    		ref_scene.saveImagePlusInModelDirectory(
+    				null,          // String    suffix,
+    				imp_disp_maps);// ImagePlus imp
+    	}
     	return nadir_pXpYD;
     }