Fix: refresh v_eff again after updating XC type

[maki49]

to prevent adding an extra PBE potential onto the hybrid Hamiltonian in the 1st iter of the EXX loop

Fix #7839

[Copilot]

Pull request overview

Fixes Issue #7839 by ensuring v_eff is refreshed immediately after the XC functional switches from the first (PBE/GGA) loop to the hybrid/EXX loop, preventing the first EXX iteration from building a Hamiltonian with a stale GGA v_eff and then adding EXX on top (double-counting exchange).

Changes:

• In the LRI EXX path, detect the two_level_step 0→1 transition after exx_after_converge() and force a potential refresh via ElecState::cal_converged().
• In the LIP solver EXX path, apply the same refresh on the 0→1 transition in iter_finish() to avoid carrying stale v_eff into the first EXX iteration.
• Add explanatory comments documenting why the refresh is required at the transition point.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
source/source_lcao/module_ri/exx_lri_interface.hpp	Refreshes v_eff via cal_converged() on the 0→1 EXX two-level transition after switching XC type.
source/source_esolver/esolver_ks_lcaopw.cpp	Applies the same v_eff refresh on the solver-side 0→1 transition for the LIP EXX workflow.

Suppressed comments (1)

source/source_esolver/esolver_ks_lcaopw.cpp:236

• Rule: Add focused tests for key features, bug fixes, INPUT behavior changes, heterogeneous kernels, and core-module refactors.
  Severity: warning
  Location: source/source_esolver/esolver_ks_lcaopw.cpp:233-236
  Reason: This change fixes a two-level EXX/hybrid transition bug (Issue #7839) but the PR does not add a regression test, despite the repository having C++ test infrastructure (e.g. source/source_esolver/test/ and source/source_lcao/module_ri/test/).
  Suggested action: Add a focused regression test that exercises the 0->1 XC switch and verifies the first EXX-iteration Hamiltonian/eigenvalues are not polluted by a stale GGA v_eff (e.g. the reported H2 SZ HF case or a smaller unit-level check around the XC switch + potential refresh).
  Exception: human approval required

            if (!conv_esolver && two_level_step_before == 0 && this->two_level_step == 1)
            {
                this->pelec->cal_converged();
            }

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