feat(Rosenbrock): 1M donor / coupled / exact modes on the unified framework

[haakon-e]

What this adds

Adds the 1-moment (Microphysics1Moment) path to the RosenbrockAverage framework from the previous PR. It introduces three presets:

• rosenbrock_donor(): DonorJacobian, the donor-based linearization M, reproducing LinearizedAverage (they agree to round-off in Float64).
• rosenbrock_coupled(): CoupledDonorJacobian, the donor matrix plus the vapor-competition (WBF) coupling, and corrects the sign of the snow source from cloud liquid.
• rosenbrock_exact(): the exact ForwardDiff Jacobian with the growth term taken explicitly and a saturation adjustment. Several 1M kernels were modified to accept dual numbers so ForwardDiff can differentiate the tendency.

Donor versus exact

The exact Jacobian costs about 2.5× the donor matrix per call. The donor matrix omits cross-couplings that in mixed-phase conditions exceed the diagonal, so at a given number of substeps the exact Jacobian is more accurate there; coupled restores the dominant vapor-competition coupling at the donor option's cost.

Testing

1M tests: rosenbrock_donor() ≡ LinearizedAverage(), the keyword constructor, all three presets return finite tendencies, and convergence against a fine explicit reference; zero-allocation and JET checks in Float64 and Float32.

[haakon-e]

This change is part of the following stack:

• feat(P3): Gauss-Legendre quadrature, integrand breakpoints -> GL(6) default #741
  • feat(Rosenbrock): unified RosenbrockAverage substepping framework + 2M+P3 exact-AD mode #726
    • feat(Rosenbrock): 1M donor / coupled / exact modes on the unified framework #731 ◀
      • feat(Rosenbrock): post-solve per-process verbose diagnostics #732
        • fix(Rosenbrock): saturation adjustment on max(S_ice, S_liq) #737
          • perf(BMT): recover the primal tendency from the Rosenbrock Jacobian pass #742
            • feat(BMT): analytic ManualJacobian for the 2M+P3 Rosenbrock substep #743
              • feat(BMT): coupled Tier-3 donor linearization for the 2M+P3 ManualJacobian #744

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