Migrate sslp harness to include a generic_cylinders.py entry

[DLWoodruff]

Summary

sslp.py already exposes scenario_creator, scenario_names_creator, kw_creator, inparser_adder, scenario_denouement, and sample_tree_scen_creator, so the generic driver can run it. All the flags used by sslp_cylinders.py (--instance-name, --sslp-data-path, --surrogate-nonant, --integer-relax-then-enforce, --reduced-costs-rho, --use-primal-dual-rho-updater, etc.) are already registered through cfg in generic_cylinders too, so the parallel entry can use the same options.

• Archive examples/sslp/sslp_ef.py (no callers anywhere) under examples/sslp/archive/.
• examples/run_all.py: add a generic_cylinders.py --module-name sslp entry paralleling the retained sslp_cylinders.py one.
• doc/src/examples.rst: reword the sslp section to say runs go through the generic driver by default and that sslp_cylinders.py is retained as the worked custom-driver example.

Retained: sslp.py (model, also the scenario_creator.rst surrogate-nonant example), sslp_cylinders.py (rst-referenced), and sslp_demo.bash.

Test plan

• mpiexec -np 4 python -m mpi4py ../../mpisppy/generic_cylinders.py --module-name sslp --instance-name=sslp_15_45_10 --sslp-data-path=./data --integer-relax-then-enforce --integer-relax-then-enforce-ratio=0.8 --lagrangian --reduced-costs-rho --max-iterations=20 --default-rho=1e-6 --reduced-costs --rc-fixer --xhatshuffle --linearize-proximal-terms --rel-gap=0.0 --surrogate-nonant --use-primal-dual-rho-updater --primal-dual-rho-update-threshold=10 --solver-name=gurobi_persistent — runs, converges to ~4.7% cylinder gap after 20 iters
• ruff check examples/run_all.py
• CI run_all job on this PR

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.72%. Comparing base (b726347) to head (8b0ad25).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #664      +/-   ##
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+ Coverage   70.71%   70.72%   +0.01%     
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  Files         153      153              
  Lines       19005    19005              
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+ Hits        13439    13441       +2     
+ Misses       5566     5564       -2     

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