Explain the theorem baryogenesisMechanismCount from IndisputableMonolith.Cosmology.BaryogenesisFromJCost.

The theorem baryogenesisMechanismCount proves that Fintype.card BaryogenesisMechanism = 5. It follows directly from the inductive definition of BaryogenesisMechanism with exactly five constructors (leptogenesis, electroWeak, affleckDine, cold, GUT) and the Fintype instance, with the proof completed by decide. The module documentation states that these five mechanisms correspond to configDim D = 5. The result is packaged into the BaryogenesisCert structure alongside the equilibrium theorem matter_balance_equilibrium (Jcost 1 = 0) and the asymmetry theorem asymmetry_positive_cost (0 < Jcost r for 0 < r ≠ 1).