fix(esolver): sort DeePMD MD neighbors by distance

[19hello]

Reminder

• I have read AGENTS.md and docs/developers_guide/agent_governance.md.
• I have linked the related issue below.
• I have added a focused unit test for the neighbor sorting logic.
• I have listed the exact verification commands and results.
• I have described the user-visible behavior change.
• I have explained the core-module impact.
• No governance exception is requested.

Linked Issue

Fixes #8071

Unit Tests and/or Case Tests for my changes

• Commands run:

  cmake -S . -B build_issue8071 \
    -DENABLE_MPI=ON \
    -DENABLE_LCAO=OFF \
    -DENABLE_OPENMP=OFF \
    -DBUILD_TESTING=ON \
    -DGIT_SUBMODULE=OFF
  
  CCACHE_DISABLE=1 cmake --build build_issue8071 \
    --target MODULE_ESOLVER_esolver_dp_test -j2
  
  OMP_NUM_THREADS=1 ctest --test-dir build_issue8071 -V \
    -R MODULE_ESOLVER_esolver_dp_test
  

The issue reproduction was also run with the provided DeepMD comparison script:

PYTHONPATH=/tmp/issue8071_pydeps
LD_LIBRARY_PATH=/tmp/mpichvenv/lib:/tmp/issue8071_pydeps
TF_INTRA_OP_PARALLELISM_THREADS=1
TF_INTER_OP_PARALLELISM_THREADS=1
OMP_NUM_THREADS=1
python3 compare_issue8071.py . frozen_seed1.pth

• Result summary:

  • The modified esolver_dp.cpp and the new unit test compile successfully.

  • The reproduction confirms that the original neighbor ordering causes:

    RMSE = 1.6590e-02
    MAX = 7.0008e-02

  • Sorting neighbors by distance reduces the discrepancy to:

    RMSE = 1.8392e-05
    MAX = 6.0702e-05

  • The root cause reported in issue [Bug] v3.11.0-beta10: esolver_type=dp forces deviate from model predictions (MDCell neighbor-list path) #8071 is therefore confirmed.

• Checks not run, with reason:

  • The CTest executable could not start because of a local BLAS/ScaLAPACK runtime conflict:

    libblas.so.3: undefined symbol: gotoblas

  • The DeePMD-enabled test target reached compilation of the modified production source, but final linking was blocked by the locally installed DeePMD 2.2.11/TensorFlow dependency setup.

What's changed?

• DeePMD MD neighbor lists are now sorted by the physical distance from the central atom before constructing InputNlist.
• The sorted neighbor storage remains alive until the DeePMD computation completes.
• A focused unit test verifies distance ordering and deterministic index ordering for equal distances.
• This fixes force discrepancies caused by different neighbor ordering between ABACUS and native DeepMD. The neighbor set was already correct, but se_e2_a may truncate the list according to sel, making the order significant.

Governance Notes

• INPUT/docs changes:
  • None. No INPUT parameter or user-facing input behavior was changed.
• Core module impact:
  • The change is limited to ESolver_DP, specifically the MDCell-to-DeePMD InputNlist adapter.
  • It does not modify HSolver, ElecState, Hamilt, Operator, or Psi.
  • Generic neighbor-list construction is unchanged.
• Exceptions requested:
  • None.
• Scope note:
  • The separate DPA-2/repformers ghost-embedding communication issue is intentionally not addressed in this PR. That issue concerns missing distributed communication metadata such as nswap, sendlist, sendproc, and world, and is independent of the neighbor-ordering bug fixed here.