v2.1.0 — Covariate-adjusted model + workflow diagram

Changes since v2.0.0

• Primary DE model adjusted for sex covariate (~ condition + gender). Addresses the main biological weakness: unadjusted model despite having sex metadata. Results regenerated: 1,773 DE genes (was 1,902), 99.8% sign concordance with full cohort.
• Workflow diagram added to README (ASCII pipeline visualization).
• NA gender filtering added before balanced sampling and full-cohort analysis.
• All figures, tables, and tests regenerated with the covariate-adjusted model. CI passes including full pipeline rebuild.