fix(cmake): don't link SHARED modules against libpython in FindPython mode

Python_add_library() hard-links non-MODULE libraries against
Python::Python. On macOS with a statically linked interpreter (e.g.
uv / python-build-standalone), importing such a module loads a second,
uninitialized copy of the Python runtime and aborts with a fatal
PyInterpreterState_Get error. Bypass python_add_library for SHARED and
link pybind11::module instead of pybind11::embed, matching the classic
pybind11Tools.cmake behavior.

Assisted-by: ClaudeCode:claude-fable-5

tools/pybind11NewTools.cmake

diff --git a/tools/pybind11NewTools.cmake b/tools/pybind11NewTools.cmake
index b0fe207..f9202b9 100644
--- a/tools/pybind11NewTools.cmake
+++ b/tools/pybind11NewTools.cmake
@@ -266,7 +266,13 @@
     set(lib_type MODULE)
   endif()
 
-  if("${_Python}" STREQUAL "Python")
+  if(lib_type STREQUAL "SHARED")
+    # Bypass python_add_library, which links SHARED libraries against libpython.
+    # An extension module must not link libpython on macOS; with a statically
+    # linked interpreter (e.g. python-build-standalone) that loads a second
+    # Python runtime and aborts on import. Matches classic pybind11Tools.cmake.
+    add_library(${target_name} SHARED ${ARG_UNPARSED_ARGUMENTS})
+  elseif("${_Python}" STREQUAL "Python")
     python_add_library(${target_name} ${lib_type} ${ARG_UNPARSED_ARGUMENTS})
   elseif("${_Python}" STREQUAL "Python3")
     python3_add_library(${target_name} ${lib_type} ${ARG_UNPARSED_ARGUMENTS})
@@ -276,10 +282,10 @@
 
   target_link_libraries(${target_name} PRIVATE pybind11::headers)
 
-  if(lib_type STREQUAL "MODULE")
-    target_link_libraries(${target_name} PRIVATE pybind11::module)
-  else()
+  if(lib_type STREQUAL "STATIC")
     target_link_libraries(${target_name} PRIVATE pybind11::embed)
+  else()
+    target_link_libraries(${target_name} PRIVATE pybind11::module)
   endif()
 
   # -fvisibility=hidden is required to allow multiple modules compiled against