Metal integration test: the CPU comparison runs on a rotation experiment

Stills keep overloads as lower bounds on CPU/CUDA but not yet on Metal, an accepted platform difference
to be fixed. On a rotation experiment both engines flag the overloads as before, so the bit-identity
comparison stays meaningful. The engine reads the rotation flag only for that decision.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015CeEGgpKdfkCTJb3YNMJcu

tests/BraggIntegrationEngineMetalTest.cpp

@@ -113,6 +113,9 @@ DiffractionExperiment MakeExperiment(const DetectorSetup &det, const Case &c) {
     x.DetectorDistance_mm(100.0f).IncidentEnergy_keV(WVL_1A_IN_KEV)
      .BeamX_pxl(0.4f * static_cast<float>(x.GetXPixelsNum()))
      .BeamY_pxl(0.55f * static_cast<float>(x.GetYPixelsNum()));
+    // Rotation: stills keep overloads as lower bounds on CPU/CUDA, but not yet on Metal (platform difference, to be fixed).
+    x.Goniometer(GoniometerAxis("omega", 0.0f, 0.1f, Coord(-1, 0, 0), {}));
+    x.ImportIndexingSettings(IndexingSettings().RotationIndexing(true));
     x.BandwidthFWHM(c.bandwidth);
     BraggIntegrationSettings s;
     s.Integrator(c.mode).Overlap(c.overlap).BackgroundRadialCorrection(c.radial).StencilKSigma(c.stencil_k)