Fix: remove .bak file, update comments and warnings in module_dh

[maki49]

• Remove nonlocal_dh_hpp.bak
• Update comments about the missing multi-k exx H and dH
• If multi-k exx H or dH is requested, WARNING_QUIT rather than silently wrong

I do not change GlobalC and PARAM as passed parameters, because it will cause a large diff, and this PR is a fix but not a refactor.
Using GlobalC and PARAM is an allowed "error", but still fails agent governance check.

[Copilot]

Pull request overview

This PR cleans up an accidental backup file and tightens behavior around EXX matrix output so unsupported configurations fail loudly rather than producing incomplete/incorrect output.

Changes:

• Removes nonlocal_dh.hpp.bak from the repository.
• Updates comments in WriteHParams / WriteDHParams to document that EXX output helpers are gamma-only.
• Adds WARNING_QUIT guards to reject unsupported multi‑k EXX output requests (with a clear message) instead of silently omitting EXX contributions.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
source/source_lcao/module_operator_lcao/nonlocal_dh.hpp.bak	Removes an obsolete/accidental backup header from the repo.
source/source_io/module_hs/write_H_terms.h	Clarifies that EXX output interfaces are gamma-only and explains why they are not templated.
source/source_io/module_hs/write_H_terms.cpp	Adds an early WARNING_QUIT in write_h_exx for non-gamma-only execution.
source/source_io/module_dhs/write_dH.h	Clarifies gamma-only EXX derivative output constraints and rationale.
source/source_io/module_dhs/write_dH.cpp	Adds a WARNING_QUIT in write_dH_components to prevent multi-k EXX dH outputs that would silently omit EXX.