CLAUDE: Add MAX-over-v locator slice to -HYPER-RECT

Prepend velocity index 0 = max over all velocities (per scene, per pixel) to
showConvKernel5dHyperRect, and scale the display range to that slice instead
of the fixed IMP_MINMAX, so the small (~0.1) maxima are visible on open. It is
the first slice ImageJ shows - a quick map of non-empty pixels before scanning
scenes (Z) and velocities (T). Applies to both -HYPER-RECT and -DNN-HYPER-RECT.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/main/java/com/elphel/imagej/cuas/rt/CuasRTUtils.java

@@ -1685,16 +1685,20 @@ public class CuasRTUtils {
     			scene_titles[i] = String.format("scene-%03d", i);
     		}
     	}
-    	String[] v_titles = new String[num_vout];
+    	// Extra leading velocity slice (index 0) = max over all velocities, a quick locator    // By Claude on 06/13/2026
+    	// of non-empty pixels. It is the first slice ImageJ shows, and the display range below
+    	// is scaled to it so the small (~0.1) maxima are immediately visible on open.
+    	String[] v_titles = new String[num_vout + 1];
+    	v_titles[0] = "MAX (all v)";
     	for (int nvout = 0; nvout < num_vout; nvout++) {
     		int vout_v = nvout / vout_dim - vout_rad;
     		int vout_h = nvout % vout_dim - vout_rad;
-    		v_titles[nvout] = nvout + " (" + ((vout_v > 0) ? "+" : "") + vout_v +
+    		v_titles[nvout + 1] = nvout + " (" + ((vout_v > 0) ? "+" : "") + vout_v +
     				":" + ((vout_h > 0) ? "+" : "") + vout_h + ")";
     	}
 
-    	// outer dim = velocities (T = bottom slider), inner dim = scenes (Z = second slider)
-    	double [][][] pixels_hyper = new double [num_vout][num_scenes][img_width * img_height];
+    	// outer dim = velocities (T = bottom slider; index 0 = MAX-over-v), inner dim = scenes (Z = second slider)
+    	double [][][] pixels_hyper = new double [num_vout + 1][num_scenes][img_width * img_height];
     	for (double [][] d2 : pixels_hyper) for (double [] d1 : d2) Arrays.fill(d1, Double.NaN);
 
     	for (int nscene = 0; nscene < num_scenes; nscene++) {
@@ -1712,23 +1716,36 @@ public class CuasRTUtils {
     						int ix      = px_roi * sub_dim + sx;
     						int iy      = py_roi * sub_dim + sy;
     						int img_pix = iy * img_width + ix;
+    						double vmax = Double.NEGATIVE_INFINITY;                              // By Claude on 06/13/2026
     						for (int v_out_idx = 0; v_out_idx < num_vout; v_out_idx++) {
-    							pixels_hyper[v_out_idx][nscene][img_pix] = pix_data[sub_idx][v_out_idx];
+    							double v = pix_data[sub_idx][v_out_idx];
+    							pixels_hyper[v_out_idx + 1][nscene][img_pix] = v;                 // velocities shifted by 1
+    							if (v > vmax) vmax = v;
     						}
+    						pixels_hyper[0][nscene][img_pix] = vmax;                              // leading MAX-over-v slice
     					}
     				}
     			}
     		}
     	}
 
+    	// Display range from the MAX-over-v slice (the one that opens first), so non-empty      // By Claude on 06/13/2026
+    	// pixels are auto-visible; velocity slices share it (their values are <= the max).
+    	double disp_min = Double.POSITIVE_INFINITY, disp_max = Double.NEGATIVE_INFINITY;
+    	for (double [] sc : pixels_hyper[0]) for (double v : sc) if (!Double.isNaN(v)) {
+    		if (v < disp_min) disp_min = v;
+    		if (v > disp_max) disp_max = v;
+    	}
+    	if (!(disp_max > disp_min)) { disp_min = IMP_MINMAX[0]; disp_max = IMP_MINMAX[1]; }       // fallback (empty/flat)
+
     	ImagePlus imp = ShowDoubleFloatArrays.showArraysHyperstack(
-    			pixels_hyper, // double[num_vout][num_scenes][img_w*img_h]
+    			pixels_hyper, // double[num_vout+1][num_scenes][img_w*img_h]
     			img_width,
     			title,
     			scene_titles, // Z slider (second)
     			v_titles,     // T slider (bottom)
     			false);
-    	imp.setDisplayRange(IMP_MINMAX[0], IMP_MINMAX[1]);
+    	imp.setDisplayRange(disp_min, disp_max);
     	return imp;
     }