CLI: document lens map options

src/main.c

@@ -324,6 +324,10 @@ static void print_help(const char *program) {
         "  --all-sky-catalog DIR          Lazy-loaded all-sky catalog directory (default: disabled)\n"
         "  --output PATH                  Tonemapped image path (default: ", stdout);
   printf("%s)\n", default_output_path);
+  fputs("  --lens-map-output FILE         Save finalized ray-traced lens map; keeps rendering normally\n"
+        "  --lens-map-input FILE          Re-render a saved map without observer, spacetime, or ray tracing\n"
+        "                                (map width, height, and FOV are fixed; mutually exclusive with --lens-map-output)\n",
+        stdout);
   fputs("  --write-catalog PATH           Write the generated test catalog and exit (default: disabled)\n"
 #ifdef ENABLE_HDR_OUTPUT
         "  --hdr-output                   Also write a single-frame linear HDR FITS file (default: disabled)\n"