refactor(dftu): move DFT+U operator from module_operator_lcao to module_dftu

Move DFTU/OperatorDFTU<OperatorLCAO> operator implementation files
(dftu.hpp, dftu_lcao.h/cpp, dftu_fs.cpp, op_dftu_lcao.h/cpp) and the
related unit test (test_dftu.cpp -> dftu_lcao_test.cpp) from
module_operator_lcao to module_dftu. This is a step toward removing
module_operator_lcao and grouping DFT+U code by physical domain.

CMake changes:
- module_dftu CMakeLists adds the 3 cpp files guarded by ENABLE_LCAO,
  since module_dftu is unconditionally added by source_lcao while
  these files depend on operator_lcao.h
- module_operator_lcao CMakeLists drops the 3 cpp files
- source_lcao CMakeLists drops the 3 cpp entries from the hamilt_lcao
  OBJECT library (now provided by the dftu OBJECT library)
- New dftu_lcao_test target guarded by ENABLE_LCAO AND ENABLE_MPI
  matches the original MODULE_LCAO_operator_dftu_test build condition

Include path updates in 5 external call sites plus op_dftu_lcao.h
internal operator_lcao.h path (changed from same-directory relative
to full path since the file is no longer co-located).

Verified: cmake configure, make abacus_max_para + dftu_lcao_test,
and ctest dftu_pw_test/dftu_core_test/dftu_operator_test/dftu_lcao_test
all pass; agent_governance_check reports only include-path change
warnings with no errors.

Author: abacus_fixer

source/source_io/module_hs/write_vxc.hpp

@@ -4,7 +4,7 @@
 #include "source_base/parallel_reduce.h"
 #include "source_base/module_container/base/third_party/blas.h"
 #include "source_base/module_external/scalapack_connector.h"
-#include "source_lcao/module_operator_lcao/op_dftu_lcao.h"
+#include "source_lcao/module_dftu/op_dftu_lcao.h"
 #include "source_lcao/module_operator_lcao/veff_lcao.h"
 #include "source_hamilt/module_xc/exx_info.h"
 #ifdef __EXX

source/source_io/module_hs/write_vxc_r.hpp

@@ -2,7 +2,7 @@
 #define __WRITE_VXC_R_H_
 #include "source_io/module_parameter/parameter.h"
 #include "source_io/module_hs/write_hs_sparse.h"
-#include "source_lcao/module_operator_lcao/op_dftu_lcao.h"
+#include "source_lcao/module_dftu/op_dftu_lcao.h"
 #include "source_lcao/module_operator_lcao/veff_lcao.h"
 #include "source_lcao/spar_hsr.h"
 #ifdef __EXX

source/source_lcao/CMakeLists.txt

@@ -15,7 +15,6 @@ if(ENABLE_LCAO)
         module_operator_lcao/veff_lcao.cpp
         module_operator_lcao/veff_dh.cpp
         module_operator_lcao/meta_lcao.cpp
-        module_operator_lcao/op_dftu_lcao.cpp
         module_operator_lcao/deepks_lcao.cpp
         module_operator_lcao/op_exx_lcao.cpp
         module_operator_lcao/overlap.cpp
@@ -32,8 +31,6 @@ if(ENABLE_LCAO)
         module_operator_lcao/td_pot_hybrid_fs.cpp
         module_operator_lcao/dspin_lcao.cpp
         module_operator_lcao/dspin_fs.cpp
-        module_operator_lcao/dftu_lcao.cpp
-        module_operator_lcao/dftu_fs.cpp
         module_operator_lcao/operator_fs_utils.cpp
         setup_dftu_lcao.cpp
         pulay_fs_center2.cpp

source/source_lcao/force_stress_lcao.cpp

@@ -20,7 +20,7 @@
 #include "source_lcao/module_deepks/lcao_deepks_io.h" // mohan add 2024-07-22
 #include "source_lcao/module_deepks/deepks_force.h"
 #endif
-#include "source_lcao/module_operator_lcao/dftu_lcao.h"
+#include "source_lcao/module_dftu/dftu_lcao.h"
 #include "source_lcao/module_operator_lcao/dspin_lcao.h"
 #include "source_lcao/module_operator_lcao/nonlocal.h"
 #include "source_lcao/module_operator_lcao/ekinetic.h"

source/source_lcao/hamilt_lcao.cpp

@@ -31,12 +31,12 @@
 #include "source_lcao/module_deltaspin/spin_constrain.h"
 #include "source_hamilt/module_hcontainer/hcontainer_funcs.h"
 #include "source_hsolver/hsolver_lcao.h"
-#include "module_operator_lcao/dftu_lcao.h"
+#include "module_dftu/dftu_lcao.h"
 #include "module_operator_lcao/dspin_lcao.h"
 #include "module_operator_lcao/ekinetic.h"
 #include "module_operator_lcao/meta_lcao.h"
 #include "module_operator_lcao/nonlocal.h"
-#include "module_operator_lcao/op_dftu_lcao.h"
+#include "module_dftu/op_dftu_lcao.h"
 #include "module_operator_lcao/op_exx_lcao.h"
 #include "module_operator_lcao/overlap.h"
 #include "module_operator_lcao/td_ekinetic_lcao.h"

source/source_lcao/module_dftu/CMakeLists.txt

@@ -8,6 +8,14 @@ list(APPEND objects
       dftu_hamilt.cpp
 )
 
+if(ENABLE_LCAO)
+  list(APPEND objects
+        dftu_lcao.cpp
+        dftu_fs.cpp
+        op_dftu_lcao.cpp
+  )
+endif()
+
 add_library(
     dftu
     OBJECT