fix(filter): harden MTRSimFilter preflight + conventions per review

- Add zero-spacing guard (-13006) before dim() divisions in preflightImpl
- Update Physical Size help text to document the 2D (Z=0) mode
- Change physicalSize/physicalSpacing members from std::vector<float> to
  std::vector<float32> to match what executeImpl reads from filterArgs
- Change outputs separator label to "Output Data Object(s)" (matches ReadMTRSimODFFilter)
- Remove premature #include "simplnx/DataStructure/DataArray.hpp" from stub MTRSim.cpp
- Add preflight test for Theta List rows with wrong column count (-13005)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: imikejackson

src/MTRSim/Filters/Algorithms/MTRSim.cpp

@@ -1,7 +1,5 @@
 #include "MTRSim.hpp"
 
-#include "simplnx/DataStructure/DataArray.hpp"
-
 using namespace nx::core;
 
 // -----------------------------------------------------------------------------

src/MTRSim/Filters/Algorithms/MTRSim.hpp

@@ -17,8 +17,8 @@ struct MTRSIM_EXPORT MTRSimInputValues
   std::vector<DataPath> odfComponentPaths;
   std::vector<std::vector<double>> volumeFractions; // 1 row x N cols
   std::vector<std::vector<double>> thetaList;       // M rows x 3 cols
-  std::vector<float> physicalSize;                  // [x,y,z] microns
-  std::vector<float> physicalSpacing;               // [x,y,z] microns
+  std::vector<float32> physicalSize;                // [x,y,z] microns
+  std::vector<float32> physicalSpacing;             // [x,y,z] microns
   uint64 seed;
   bool generatePolarColoring;
   DataPath outputGeometryPath;

src/MTRSim/Filters/MTRSimFilter.cpp

@@ -86,7 +86,7 @@ Parameters MTRSimFilter::parameters() const
                                                           "Size/Spacing.",
                                                           thetaInfo));
   }
-  params.insert(std::make_unique<VectorFloat32Parameter>(k_PhysicalSize_Key, "Physical Size (microns)", "Domain extent X,Y,Z.", std::vector<float32>{38.1f, 12.7f, 0.0f},
+  params.insert(std::make_unique<VectorFloat32Parameter>(k_PhysicalSize_Key, "Physical Size (microns)", "Domain extent X, Y, Z in microns. Set Z = 0 to generate a single-layer (2D) microstructure.", std::vector<float32>{38.1f, 12.7f, 0.0f},
                                                          std::vector<std::string>{"X", "Y", "Z"}));
   params.insert(std::make_unique<VectorFloat32Parameter>(k_PhysicalSpacing_Key, "Physical Spacing (microns)", "Voxel spacing X,Y,Z.", std::vector<float32>{0.02f, 0.02f, 0.02f},
                                                          std::vector<std::string>{"X", "Y", "Z"}));
@@ -96,7 +96,7 @@ Parameters MTRSimFilter::parameters() const
   params.insert(std::make_unique<NumberParameter<uint64>>(k_SeedValue_Key, "Seed Value", "The seed fed into the random generator.", std::mt19937::default_seed));
   params.insert(std::make_unique<DataObjectNameParameter>(k_SeedArrayName_Key, "Stored Seed Value Array Name", "Top-level array recording the seed used.", "MTRSim SeedValue"));
 
-  params.insertSeparator(Parameters::Separator{"Outputs"});
+  params.insertSeparator(Parameters::Separator{"Output Data Object(s)"});
   params.insertLinkableParameter(
       std::make_unique<BoolParameter>(k_GeneratePolarColoring_Key, "Generate Polar Coloring", "Create a 3-component UInt8 RGB array using the MATLAB polar color mapping.", false));
   params.insert(std::make_unique<DataGroupCreationParameter>(k_OutputGeometry_Key, "Output Image Geometry", "Path of the new microstructure Image Geometry.", DataPath({"MTR Microstructure"})));
@@ -173,6 +173,11 @@ IFilter::PreflightResult MTRSimFilter::preflightImpl(const DataStructure& dataSt
     }
   }
 
+  if(pSpacing[0] <= 0.0f || pSpacing[1] <= 0.0f)
+  {
+    return {MakeErrorResult<OutputActions>(-13006, "Physical Spacing X and Y must be greater than 0.")};
+  }
+
   const auto dim = [](float len, float sp) { return static_cast<usize>(std::max(std::lround(len / sp), 1L)); };
   const usize nx = dim(pSize[0], pSpacing[0]);
   const usize ny = dim(pSize[1], pSpacing[1]);

test/MTRSimTest.cpp

@@ -7,6 +7,7 @@
  *   2. Theta List rows < numComponents - 1 -> invalid.
  *   3. Volume Fraction values do not sum to 1.0 -> invalid.
  *   4. Happy-path args -> preflight VALID (builds geometry + array actions).
+ *   5. Theta List rows with wrong column count (2 instead of 3) -> invalid (-13005).
  */
 
 #include <catch2/catch.hpp>
@@ -146,3 +147,21 @@ TEST_CASE("MTRSim::MTRSimFilter: Rejects Volume Fraction not summing to 1.0", "[
   auto preflightResult = filter.preflight(dataStructure, args);
   SIMPLNX_RESULT_REQUIRE_INVALID(preflightResult.outputActions);
 }
+
+TEST_CASE("MTRSim::MTRSimFilter: Rejects Theta List rows with wrong column count", "[MTRSim][MTRSimFilter][ErrorPath]")
+{
+  UnitTest::LoadPlugins();
+
+  DataStructure dataStructure;
+  const std::vector<DataPath> compPaths = BuildOdfDataStructure(dataStructure, 3);
+
+  MTRSimFilter filter;
+  Arguments args = MakeValidArgs(compPaths);
+  // 2 rows supplied (enough for 3 components: needs >= 2), but each row has only 2
+  // columns instead of 3 — must trigger the column-count check (-13005), not the
+  // row-count check (-13004).
+  args.insertOrAssign(MTRSimFilter::k_ThetaList_Key, DynamicTableParameter::ValueType{{0.1, 0.45}, {0.08, 0.37}});
+
+  auto preflightResult = filter.preflight(dataStructure, args);
+  SIMPLNX_RESULT_REQUIRE_INVALID(preflightResult.outputActions);
+}