CLAUDE: Add nadir_um_en/sigma/weight parameters for SIFT-tuned UM on nadir renders

Add three dedicated unsharp-mask parameters to IntersceneMatchParameters:
  nadir_um_en     (boolean, default false) - enable UM on nadir images
  nadir_um_sigma  (double,  default 2.0)   - Gaussian sigma in pixels
  nadir_um_weight (double,  default 1.0)   - blend weight (1.0 = 100%)

These are separate from the existing um_sigma/weight and terr_um_* / cuas_rng_um_*
parameters so they can be independently tuned for SIFT feature extraction.
LWIR nadir images with UM sigma=2 go from ~500 to ~5000 SIFT keypoints/frame.

Updated all 6 required locations: field declarations, dialog, dialog-read,
save, load, and clone.

Applied the filter in renderNadirSequence() using the existing applyUM()
helper, matching the renderSceneSequence() pattern.
Co-authored-by: Claude <claude@elphel.com>

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

@@ -1144,6 +1144,9 @@ min_str_neib_fpn	0.35
 	public double   fgnd_normal_damping =  0.001; // Damping parameter for planes. Pull planes to horizontal when there is not enough data for tilts.
 	
     public  boolean nadir_gen =           false; // generate per-scene nadir perspective images for OpenMVS input
+    public  boolean nadir_um_en =         false; // apply unsharp mask to nadir images for SIFT feature enhancement
+    public  double  nadir_um_sigma =      2.0;   // UM Gaussian sigma (pixels) for nadir images
+    public  double  nadir_um_weight =     1.0;   // UM weight for nadir images (1.0 = 100%)
     public  boolean fgnd_gen_optho =      true;  // generate orthogonal to the ground view
     public  boolean fgnd_gen_tilted =     true;  // generate tilted ground disparity view
     public  boolean fgnd_gen_scan =       false; // generate "CT scan" views
@@ -3380,6 +3383,12 @@ min_str_neib_fpn	0.35
 		gd.addMessage  ("Output files generation related to ground planes");
 		gd.addCheckbox ("Generate nadir per-scene images for OpenMVS", this.nadir_gen,
 				"Render each scene from its own camera position (no terrain warp), for use as OpenMVS/COLMAP input.");
+		gd.addCheckbox    ("Apply UM to nadir images",               this.nadir_um_en,
+				"Apply unsharp mask to nadir renders to enhance features for SIFT.");
+		gd.addNumericField("Nadir UM sigma",   this.nadir_um_sigma,  5,7, "pix",
+				"Nadir unsharp mask Gaussian sigma.");
+		gd.addNumericField("Nadir UM weight",  this.nadir_um_weight, 5,7, "",
+				"Nadir unsharp mask weight (1.0=100%).");
 		gd.addCheckbox ("Generate orthogonal to the ground view",   this.fgnd_gen_optho,
 				"Generate relative to the ground plane view, minimizing anisotropic distortions.");
 		gd.addCheckbox ("Generate tilted-ground view",              this.fgnd_gen_tilted,
@@ -4817,6 +4826,9 @@ min_str_neib_fpn	0.35
 		this.fgnd_normal_damping =      gd.getNextNumber();
 		
 		this.nadir_gen =                gd.getNextBoolean();
+		this.nadir_um_en =              gd.getNextBoolean();
+		this.nadir_um_sigma =           gd.getNextNumber();
+		this.nadir_um_weight =          gd.getNextNumber();
 		this.fgnd_gen_optho =           gd.getNextBoolean();
 		this.fgnd_gen_tilted =          gd.getNextBoolean();
 		this.fgnd_gen_scan =            gd.getNextBoolean();
@@ -6113,6 +6125,9 @@ min_str_neib_fpn	0.35
 		properties.setProperty(prefix+"fgnd_normal_damping",  this.fgnd_normal_damping+""); // double
 
 		properties.setProperty(prefix+"nadir_gen",             this.nadir_gen+"");           // boolean
+		properties.setProperty(prefix+"nadir_um_en",          this.nadir_um_en+"");         // boolean
+		properties.setProperty(prefix+"nadir_um_sigma",       this.nadir_um_sigma+"");      // double
+		properties.setProperty(prefix+"nadir_um_weight",      this.nadir_um_weight+"");     // double
 		properties.setProperty(prefix+"fgnd_gen_optho",       this.fgnd_gen_optho+"");      // boolean
 		properties.setProperty(prefix+"fgnd_gen_tilted",      this.fgnd_gen_tilted+"");     // boolean
 		properties.setProperty(prefix+"fgnd_gen_scan",        this.fgnd_gen_scan+"");       // boolean
@@ -7392,6 +7407,9 @@ min_str_neib_fpn	0.35
 		if (properties.getProperty(prefix+"fgnd_normal_damping")!=null)  this.fgnd_normal_damping=Double.parseDouble(properties.getProperty(prefix+"fgnd_normal_damping"));
 
 		if (properties.getProperty(prefix+"nadir_gen")!=null)             this.nadir_gen=Boolean.parseBoolean(properties.getProperty(prefix+"nadir_gen"));
+		if (properties.getProperty(prefix+"nadir_um_en")!=null)          this.nadir_um_en=Boolean.parseBoolean(properties.getProperty(prefix+"nadir_um_en"));
+		if (properties.getProperty(prefix+"nadir_um_sigma")!=null)       this.nadir_um_sigma=Double.parseDouble(properties.getProperty(prefix+"nadir_um_sigma"));
+		if (properties.getProperty(prefix+"nadir_um_weight")!=null)      this.nadir_um_weight=Double.parseDouble(properties.getProperty(prefix+"nadir_um_weight"));
 		if (properties.getProperty(prefix+"fgnd_gen_optho")!=null)       this.fgnd_gen_optho=Boolean.parseBoolean(properties.getProperty(prefix+"fgnd_gen_optho"));
 		if (properties.getProperty(prefix+"fgnd_gen_tilted")!=null)      this.fgnd_gen_tilted=Boolean.parseBoolean(properties.getProperty(prefix+"fgnd_gen_tilted"));
 		if (properties.getProperty(prefix+"fgnd_gen_scan")!=null)        this.fgnd_gen_scan=Boolean.parseBoolean(properties.getProperty(prefix+"fgnd_gen_scan"));
@@ -8652,6 +8670,9 @@ min_str_neib_fpn	0.35
 		imp.fgnd_normal_damping   = this.fgnd_normal_damping;
 
 		imp.nadir_gen =        		this.nadir_gen;
+		imp.nadir_um_en =           this.nadir_um_en;
+		imp.nadir_um_sigma =        this.nadir_um_sigma;
+		imp.nadir_um_weight =       this.nadir_um_weight;
 		imp.fgnd_gen_optho =  		this.fgnd_gen_optho;
 		imp.fgnd_gen_tilted =  		this.fgnd_gen_tilted;
 		imp.fgnd_gen_scan =    		this.fgnd_gen_scan;

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

@@ -10982,7 +10982,16 @@ java.lang.NullPointerException
     		}
     	}
     	if (stack_scenes == null) return null;
-    	return new ImagePlus(suffix, stack_scenes);
+    	ImagePlus imp_result = new ImagePlus(suffix, stack_scenes);
+    	// Apply unsharp mask to enhance SIFT features in LWIR nadir images
+    	if (clt_parameters.imp.nadir_um_en && !toRGB) {
+    		imp_result = applyUM(
+    				suffix,                              // final String title,
+    				imp_result,                          // final ImagePlus imp,
+    				clt_parameters.imp.nadir_um_sigma,   // final double um_sigma,
+    				clt_parameters.imp.nadir_um_weight); // final double um_weight)
+    	}
+    	return imp_result;
     }
 
     public static QuadCLT[] selectScenes(