Fix elecstate energy unit test link dependencies

[kluonju]

Motivation

• Resolve link-time undefined references for elecstate::H_Hartree_pw::v_hartree and elecstate::makov_payne_correction when building the MODULE_ESTATE_elecstate_energy unit test by ensuring the test links the planewave implementation and compiles the provider sources.

Description

• Update source/source_estate/test/CMakeLists.txt to add planewave_serial to the LIBS for MODULE_ESTATE_elecstate_energy and to include ../makov_payne.cpp and ../module_pot/H_Hartree_pw.cpp in the test SOURCES so the missing symbols are defined at link time.

Testing

• Ran git diff --check, which passed; attempted to configure the test build with cmake -DBUILD_TESTING=ON -DENABLE_MPI=ON but configuration failed due to missing MPI; a second cmake attempt with -DENABLE_MPI=OFF failed due to missing FFTW3, so a full build/test could not be completed in this environment.

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Codex Task