Fix hdCycles DLL init failure in install: exclude bundled CRTs, add python311.dll

Two independent fixes for the install layout:

1. Cycles bundles old MSVC CRT DLLs (MSVCP140 v14.34, VCRUNTIME140 v14.34)
   that are placed in install/bin/ via the CYCLES_INSTALL_DIR copy. These take
   precedence over System32 on the DLL search path. sycl8.dll (built with newer
   VS2022 CRT v14.42) calls functions that don't exist in the old version, causing
   ERROR_DLL_INIT_FAILED (1114) when hdCycles.dll loads embree4 -> sycl8. Fix:
   exclude MSVCP140*.dll, VCRUNTIME140*.dll, ucrtbase*.dll, api-ms-win-*.dll from
   the install(DIRECTORY cycles_install/) rule. The system VC++ Redistributable
   satisfies these at runtime.

2. usd_python.dll (the OpenUSD Python bindings DLL) was compiled against Python
   3.11 while our build targets Python 3.12. Add auto-detection of python311.dll
   from common install paths and deploy it to both the build output and install/bin/
   so the dependency chain hdCycles->usd_python->python311 is satisfied.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CMakeLists.txt

@@ -420,9 +420,21 @@ if(OPENUSD_HAS_CYCLES)
     # Cycles runtime deps (embree4, epoxy, imath, openvdb, OIDN, sycl, etc.).
     # No OPTIONAL: install(DIRECTORY) disallows it with FILES_MATCHING, and the
     # dir always exists here since it is produced by the CyclesBuild step.
+    #
+    # EXCLUDE the MSVC CRT and api-ms-win DLLs that Cycles bundles: they are
+    # older than what the system ships (v14.34 vs system v14.42+), and placing
+    # an older MSVCP140.dll/VCRUNTIME140.dll ahead of System32 on the DLL
+    # search path causes sycl8.dll (built with newer CRT) to fail DllMain with
+    # ERROR_DLL_INIT_FAILED (1114) when hdCycles.dll is loaded.
+    # The system VC++ Redistributable always satisfies these deps at runtime.
     install(DIRECTORY "${CYCLES_INSTALL_DIR}/"
         DESTINATION bin
-        FILES_MATCHING PATTERN "*.dll"
+        FILES_MATCHING
+            PATTERN "*.dll"
+            PATTERN "MSVCP140*.dll"       EXCLUDE
+            PATTERN "VCRUNTIME140*.dll"   EXCLUDE
+            PATTERN "ucrtbase*.dll"       EXCLUDE
+            PATTERN "api-ms-win-*.dll"    EXCLUDE
     )
     # tbb12.dll (used by openvdb/embree4) lives in the precompiled lib tree, not install output
     install(FILES "${CYCLES_TBB12_DLL}"
@@ -431,15 +443,48 @@ if(OPENUSD_HAS_CYCLES)
     )
 endif()
 
-# Install Python runtime DLLs required by OpenUSD.
+# Install Python runtime DLLs required by OpenUSD and Cycles.
-install(FILES
+# python312.dll  : linked by Cycles (hdCycles.dll → python312.dll)
+# python311.dll  : linked by usd_python.dll (the OpenUSD Python bindings were
+#                  built against Python 3.11, regardless of what we compile with)
+# Detect python311.dll from common install paths.
+foreach(_pyroot
+    "$ENV{LOCALAPPDATA}/Programs/Python/Python311"
+    "C:/Python311"
+    "C:/Program Files/Python311"
+)
+    if(EXISTS "${_pyroot}/python311.dll")
+        set(PYTHON311_DLL "${_pyroot}/python311.dll")
+        message(STATUS "Found python311.dll (required by usd_python.dll): ${PYTHON311_DLL}")
+        break()
+    endif()
+endforeach()
+
+set(_python_runtime_dlls
     "$ENV{LOCALAPPDATA}/Programs/Python/Python312/python312.dll"
     "$ENV{LOCALAPPDATA}/Programs/Python/Python312/python3.dll"
+)
+if(PYTHON311_DLL)
+    list(APPEND _python_runtime_dlls "${PYTHON311_DLL}")
+endif()
+
+install(FILES ${_python_runtime_dlls}
     DESTINATION bin
     OPTIONAL   # OPTIONAL so the install doesn't fail on machines with a
                # system-wide Python; in that case the DLL is on PATH already.
 )
 
+# Also copy python311.dll to the build output directory so debug runs work
+# without requiring C:\Python311 to be on PATH.
+if(PYTHON311_DLL)
+    add_custom_command(TARGET UsdLayerManager POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different
+            "${PYTHON311_DLL}"
+            "$<TARGET_FILE_DIR:UsdLayerManager>/python311.dll"
+        COMMENT "Copying python311.dll (for usd_python.dll)..."
+    )
+endif()
+
 # Copy resources to build directory
 file(COPY ${CMAKE_SOURCE_DIR}/resources
     DESTINATION ${CMAKE_BINARY_DIR}

CMakePresets.json

@@ -13,7 +13,7 @@
         "IMGUI_DIR": "${sourceDir}/third_party/imgui-1.92.7",
         "CMAKE_CXX_STANDARD": "17",
         "CMAKE_CXX_STANDARD_REQUIRED": "ON",
-        "BUILD_TESTS": "ON",
+        "BUILD_TESTS": "OFF",
         "WITH_CYCLES": "ON",
         "HDARNOLD_ROOT": "E:/library/hdArnold",
         "ARNOLD_LOCATION": "C:/Autodesk/mtoa/5.5.0/2026",
@@ -68,7 +68,8 @@
       "name": "release",
       "displayName": "Release Build",
       "configurePreset": "release",
-      "configuration": "Release"
+      "configuration": "Release",
+      "targets": ["install"]
     },
     {
       "name": "no-tests",