v0.8.0

What’s Changed

• Nonlinear (elasto-plastic) beam analysis (NonlinearBeamAnalysis) — #140
• Non-prismatic (variable-EI) elements (SectionEI) — #139
• Imposed-curvature (initial-strain) loads (add_ic, load type 6) — #139
• plus Markdown (MyST) documentation migration

Verification

• Full suite: 117 passed (incl. the new test_rejects_nonprismatic_member).
• Docs build warning-free; the prismatic-only note renders correctly in the nonlinear tutorial.