Integrate tests: maintainability of the validation scripts (monolithic catch_properties.sh, unclear tool layout) #8091

Describe the Code Quality Issue

Problem

While working on the integrate-test tooling in tests/integrate/, we hit
several maintenance pain points:

1. A 1000+-line monolithic collector. tests/integrate/tools/catch_properties.sh
   collects every kind of result line (energies, forces, stresses, DOS,
   matrices, cubes, ML, DeePKS, TDDFT, ...) into result.out in a single
   file. Finding where a given key is produced is slow, and adding a new
   kind of check means editing an ever-growing file whose output-order
   constraints are only implicit.

2. Duplicated helpers. catch_deepks_properties.sh re-defines helpers
   (sum_file, get_input_key_value, compare-script path) that also exist
   in catch_properties.sh, so the two copies can drift apart silently.

3. Hard-coded relative paths. Scripts reference helpers through
   ../../integrate/tools/... relative to the test-case working
   directory, which breaks whenever the collector is invoked with a
   different CWD and makes the scripts fragile to relocation.

4. Dead code. E.g. the compare-wfc subcommand of cube_tool.py has
   no caller, and the collector contains unreachable branches.

5. Awkward executable selection for local runs. Pointing the tests at
   a local ABACUS build requires either exporting ABACUS_EXE in every
   new shell or editing tracked files (Autotest.sh, general_info),
   which risks committing a machine-specific absolute path.

6. No documentation of the validation workflow. How result.ref /
   result.out comparison works (thresholds, per-case threshold files,
   the information-only totaltimeref line) is not written down anywhere;
   the directory name tools also does not convey that these scripts are
   the validation toolkit.

Proposal

• Split the collector into one module per result family
  (props_basic.sh, props_mat.sh, props_cube.sh, props_ml.sh,
  props_tddft.sh, props_deepks.sh) plus a shared props_common.sh,
  each exposing run_<category>_props() hooks; catch_properties.sh
  becomes a thin orchestrator that calls the hooks in the original order.

• Rename tests/integrate/tools to tests/integrate/validation_tools
  and resolve helper paths from the script's own location.

• Support an untracked, gitignored integrate/general_info.local as a
  local executable override (priority: -a flag > ABACUS_EXE >
  local file > PATH), on top of the existing ABACUS_EXE support.

• Document the validation workflow (three entry points: whole category,
  single case, collector-only) in tests/README.

• Remove the dead code.

Constraints

• The collected output must not change: result.out content and exit
  codes stay byte-for-byte identical for all existing cases (verified by
  running the old and new collectors side by side; only totaltimeref,
  the wall-time line, differs by design).

• No INPUT parameter behavior is involved, and CI (which only invokes
  Autotest.sh) keeps working unchanged.

Additional Context

No response

Task list for Issue attackers (only for developers)

• Identify the specific code file or section with the code quality issue.
• Investigate the issue and determine the root cause.
• Research best practices and potential solutions for the identified issue.
• Refactor the code to improve code quality, following the suggested solution.
• Ensure the refactored code adheres to the project's coding standards.
• Test the refactored code to ensure it functions as expected.
• Update any relevant documentation, if necessary.
• Submit a pull request with the refactored code and a description of the changes made.