rugnux: the header line and console summary print the wavelength --wavelength set

The "Header:" log line and the console note under it printed the input file's wavelength (or
the reader's 1 A placeholder where the file states none) even when --wavelength overrode it,
so a run that processed, refined and wrote everything at the given wavelength announced
another one at the top of its log. They now print the wavelength used, naming the file's
value beside it when the option replaced it. --mode scale keeps the wavelength its
reflections were integrated at, so it still prints the file's.

The report (WAVELENGTH=, XDS.INP block), the merged and unmerged MTZ, the mmCIF and the
_process.h5 were already written from the overridden experiment.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HVeDQqN9qRD57vnShzTC37

rugnux/rugnux_cli.cpp

@@ -2163,15 +2163,22 @@ int RugnuxInputRun::PrepareRugnuxInput() {
     output_provenance.collection_date = dataset->arm_date;
     {
         // The header as the file states it, before anything is measured: what a question about a run
-        // is answered from first.
+        // is answered from first. The wavelength is the one used: --wavelength, where given, is not
+        // refined later, so the file's value would be printed for a run that never used it (--mode scale
+        // keeps the wavelength its reflections were integrated at).
         const auto &x = dataset->experiment;
         const auto gonio = x.GetGoniometer();
         const auto [direct_x, direct_y] = x.GetDiffractionGeometry().GetDirectBeam_pxl();
-        logger.Info("Header: {} images, detector {} {} x {} px of {:.4f} mm, wavelength {:.5f} A, distance "
+        const bool wavelength_given = wavelength_A && mode != RugnuxMode::Scale;
+        const float used_wavelength_A = wavelength_given ? *wavelength_A : x.GetWavelength_A();
+        const std::string wavelength_source =
+                wavelength_given ? fmt::format(" (--wavelength; the file states {:.5f} A)", x.GetWavelength_A()) : "";
+        logger.Info("Header: {} images, detector {} {} x {} px of {:.4f} mm, wavelength {:.5f} A{}, distance "
                     "{:.3f} mm, beam {:.2f} {:.2f} px (direct beam {:.2f} {:.2f}), tilt {:.4f} {:.4f} deg, {}, "
                     "polarization {}",
                     reader.GetNumberOfImages(), x.GetDetectorDescription(), x.GetXPixelsNum(), x.GetYPixelsNum(),
-                    x.GetPixelSize_mm(), x.GetWavelength_A(), x.GetDetectorDistance_mm(), x.GetBeamX_pxl(),
+                    x.GetPixelSize_mm(), used_wavelength_A, wavelength_source, x.GetDetectorDistance_mm(),
+                    x.GetBeamX_pxl(),
                     x.GetBeamY_pxl(), direct_x, direct_y, x.GetPoniRot1_rad() * 180.0 / PI,
                     x.GetPoniRot2_rad() * 180.0 / PI,
                     gonio ? fmt::format("rotation from {:.3f} deg by {:.4f} deg per image", gonio->GetStart_deg(),
@@ -2181,7 +2188,7 @@ int RugnuxInputRun::PrepareRugnuxInput() {
                                               : std::string("not stated"));
         console->OnNote(fmt::format("{} images, {} {} x {} px", reader.GetNumberOfImages(),
                                     x.GetDetectorDescription(), x.GetXPixelsNum(), x.GetYPixelsNum()));
-        console->OnNote(fmt::format("{:.4f} A, {:.1f} mm, {}", x.GetWavelength_A(), x.GetDetectorDistance_mm(),
+        console->OnNote(fmt::format("{:.4f} A, {:.1f} mm, {}", used_wavelength_A, x.GetDetectorDistance_mm(),
                                     gonio ? fmt::format("{:.3f} deg per image", gonio->GetIncrement_deg())
                                           : std::string("no rotation axis")));
     }