mathlib-fp 2.3.0

Version 2.3.0 adds adaptive stiff initial-value integration to the numerical modelling toolkit.

Added

• TModellingKit.SolveStiffODE, an adaptive Alexander two-stage SDIRK2 solver with component-scaled error control.
• Analytic, forward-mode automatic, and finite-difference Jacobian modes, with Newton convergence and evaluation diagnostics.
• Cubic-Hermite dense output, backward integration, directional event detection, and accepted/rejected step counts.
• A runnable Robertson and forced-stiff example, plus numerical reference and event tests.

The existing explicit SolveODE API is unchanged. The new solver supports dense real-double systems in explicit form y' = f(t, y). It does not provide mass-matrix systems, DAEs, PDEs, or sparse and large-scale stiff solves.

The checksummed clean-archive qualification record is available in the qualification report and workflow evidence.