benchmark: add canonical Penalized CoxPH and CoxPHCV coverage

[TheHiddenObserver]

Goal

Add current canonical benchmark coverage for Penalized CoxPH paths and CoxPHCV without treating PR79/PR80 validation evidence as dashboard-ready by default.

Scope

• classify inherited PR79/PR80 artifacts and select or rerun canonical cases;
• align ties, strata, delayed entry, penalty definitions, grids, folds, scoring, refit, convergence, and external references;
• retain fit, CV, inference, and prediction timing separately;
• synchronize GPU timing and preserve failure states;
• add structured sources, parser tests, manifest registration, generated assets, and coverage-matrix updates.

Parent: #100