distr example cleanup: typo, dead code, kwarg defaults, go.bash modernization

[DLWoodruff]

Summary

Four review items from a walkthrough of examples/distr/distr.py, bundled into one PR. Independent of the phase-A work in PR #686.

• Typo + vague description. The --scalable CLI option's help string said "decides whether a sclale model is used". Fix the typo and broaden the wording to explain what the flag actually does: "generate pseudo-random data parameterized by --mnpr instead of using the hardwired 2/3/4-region datasets". Apply the same description to examples/stoch_distr/stoch_distr.py for consistency.

• Dead code in scenario_denouement. Five lines after an unconditional return (pprint/print calls) — removed.

• Misleading kwarg defaults. scenario_creator declared inter_region_dict=None, cfg=None, data_params=None, all_nodes_dict=None and then assert ... is not None on entry. For inter_region_dict and cfg this is misleading — kw_creator always passes them and the =None defaults imply optionality. Make them required kwargs and let Python's missing-arg error report the problem naturally. Keep =None defaults on data_params / all_nodes_dict (genuinely scalable-only). Rewrite the (stale) docstring to match.

• go.bash modernization (Move and generalize license re-try loop logic in PHBase #3 from the review list). Switch to generic_cylinders --admm, matching the recommendation we put at the top of admmWrapper.rst in PR ADMM doc cross-refs, BFs flow-through, stage2ef hard error #685. The legacy custom driver distr_admm_cylinders.py stays in the directory for reference; go.bash has a comment pointing at the doc rationale.

Test plan

• bash go.bash (SOLVERNAME=gurobi_persistent locally) — converges to 2.1% gap (below the 5% target)
• python -m pytest mpisppy/tests/test_admm_bundler.py — 26/26 pass
• python -m pytest mpisppy/tests/test_admmWrapper.py — 6/7 pass; the 7th (test_values) is a pre-existing flaky subprocess-capture failure that also fails on clean main (same pattern as test_stoch_admmWrapper::test_values)
• ruff check examples/distr/distr.py examples/stoch_distr/stoch_distr.py — clean

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.03%. Comparing base (fcae16f) to head (bcc267a).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #687   +/-   ##
=======================================
  Coverage   71.02%   71.03%           
=======================================
  Files         154      154           
  Lines       19252    19252           
=======================================
+ Hits        13674    13675    +1     
+ Misses       5578     5577    -1     

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