Refactor: remove source_lcao dependency from source_hsolver

[Critsium-xy]

Background

As part of dependency cleanup for source_hsolver, the target is to keep it depending only on source_estate, source_psi, source_cell, source_basis, and source_base (source_io tolerated for now).

A scan showed one direct dependency on source_lcao:

• source/source_hsolver/hsolver_lcao.cpp → #include "source_lcao/rho_tau_lcao.h", used to call LCAO_domain::dm2rho for computing the charge density after solving the Hamiltonian.

Change

HSolverLCAO::solve now delegates the charge-density calculation through a new thin wrapper ElecStateLCAO::dmToRho, instead of calling the source_lcao free function directly.

• source_estate/elecstate_lcao.{h,cpp}: add dmToRho(...), forwarding to LCAO_domain::dm2rho. source_estate already depends on source_lcao (e.g. module_gint, rho_tau_lcao.h), so this introduces no new cross-module dependency edge.
• source_hsolver/hsolver_lcao.cpp: call dynamic_cast<ElecStateLCAO<TK>*>(pes)->dmToRho(...) and remove the source_lcao include.

This mirrors the existing patterns in the codebase:

• the pexsi branch in the same function already delegates via _pes->dm2rho(...);
• the plane-wave path delegates charge computation via ElecStatePW::psiToRho.

After this change, source_hsolver has no direct source_lcao include or LCAO_domain reference.

Notes

• No functional change — pure dependency refactor; the same LCAO_domain::dm2rho is executed, just reached through the ElecState interface.
• The dynamic_cast precondition (pes is an ElecStateLCAO on the LCAO path) is already relied upon by the pre-existing pexsi branch.

[mohanchen]

OK, that's reasonable.