CLAUDE: Add transposeJagged() utility to ShowDoubleFloatArrays; refactor getNadirDisparityMaps()

Add ShowDoubleFloatArrays.transposeJagged(double[][][], int n_comp, int n_inner)
which converts the common [outer][inner][comp] layout (with null outer or inner
entries) to [outer][comp][inner] substituting NaN for nulls.  This pattern
appeared inline in getNadirDisparityMaps() and recurs in other tile-processing
code.

Refactor getNadirDisparityMaps() to replace the 12-line inline transpose loop
with a single call to the new utility, keeping the same semantics.
Co-authored-by: Claude <claude@elphel.com>

src/main/java/com/elphel/imagej/common/ShowDoubleFloatArrays.java

@@ -1189,6 +1189,41 @@ G= Y  +Pr*(- 2*Kr*(1-Kr))/Kg + Pb*(-2*Kb*(1-Kb))/Kg
 		return out_data;
 	}
 
-  
+	/**
+	 * Transpose a jagged [outer][inner][comp] array to [outer][comp][inner],
+	 * substituting NaN for null entries at either level.
+	 *
+	 * <p>This is a common pattern when tile-level results are stored as
+	 * {@code arr[frame][tile][comp]} (inner entries may be null for missing tiles,
+	 * outer entries may be null for missing frames) and need to be reorganised into
+	 * the {@code [frame][comp][tile]} layout expected by
+	 * {@link #showArraysHyperstack}.
+	 *
+	 * @param arr     source array; {@code arr[i]} may be null (whole frame absent);
+	 *                {@code arr[i][j]} may be null (individual tile absent);
+	 *                for non-null innermost entries the length must equal {@code n_comp}
+	 * @param n_comp  number of components (innermost dimension in {@code arr})
+	 * @param n_inner number of inner entries (tile count; used as second dimension of output)
+	 * @return {@code [outer][n_comp][n_inner]} array with {@link Double#NaN} substituted
+	 *         for null entries
+	 */
+	public static double[][][] transposeJagged(double[][][] arr, int n_comp, int n_inner) {
+		double[][][] out = new double[arr.length][n_comp][n_inner];
+		for (int i = 0; i < arr.length; i++) {
+			for (int c = 0; c < n_comp; c++) {
+				Arrays.fill(out[i][c], Double.NaN);
+			}
+			if (arr[i] != null) {
+				for (int j = 0; j < n_inner; j++) {
+					if (arr[i][j] != null) {
+						for (int c = 0; c < n_comp; c++) {
+							out[i][c][j] = arr[i][j][c];
+						}
+					}
+				}
+			}
+		}
+		return out;
+	}
 
 }
\ No newline at end of file

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

@@ -10883,22 +10883,11 @@ java.lang.NullPointerException
     	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)
-    				}
-    			}
-    		}
     	}
+    	// Transpose [scene][tile][3] (nulls) -> [scene][3][tile] (NaN) for showArraysHyperstack
+    	double [][][] disp_maps = ShowDoubleFloatArrays.transposeJagged(nadir_pXpYD, 3, ntiles);
     	ImagePlus imp_disp_maps = ShowDoubleFloatArrays.showArraysHyperstack(
     			disp_maps,                                              // double [][][]  pixels,
     			tilesX,                                                 // int            width,