[Code scan] Use the FindPython executable variable for f2py headers

This issue comes from a Codex global scan of deepmodeling/tbplas at commit 4d3652b3dba8eb930e4869a6d41074f62d703692.

Severity: High

`find_package(Python COMPONENTS Interpreter Development.Module NumPy REQUIRED)` provides `Python_EXECUTABLE`, but the f2py include discovery command uses the old `PYTHON_EXECUTABLE` variable. With modern CMake `PYTHON_EXECUTABLE` is empty, so the command can fail to populate `F2PY_INCLUDE_DIR`; the next line then tries to build `${F2PY_INCLUDE_DIR}/fortranobject.c`, which can resolve to an invalid `/fortranobject.c` path.

Code references:
https://github.com/deepmodeling/tbplas/blob/4d3652b3dba8eb930e4869a6d41074f62d703692/CMakeLists.txt#L7-L9
https://github.com/deepmodeling/tbplas/blob/4d3652b3dba8eb930e4869a6d41074f62d703692/CMakeLists.txt#L52-L56

Suggested fix: use `${Python_EXECUTABLE}` in the `execute_process` call and fail early if the f2py include directory cannot be resolved.

Start with CMakeLists.txt lines 7-9 and 52-56, then inspect the f2py include discovery command and the following fortranobject.c path. Update the executable variable and add the requested early failure check; done means configuration resolves F2PY_INCLUDE_DIR successfully with modern CMake.

Written by the indexing model from the issue text.