Quantum neural networks: dynamical Lie algebras and trainability

Umbrella module for the quantum-neural-network and barren-plateau development.

• QNN.DynamicalLieAlgebra — the dynamical Lie algebra of a generator set.
• QNN.Overparametrization — overparametrization capacity bound.
• QNN.Trainability — exponential-concentration / barren-plateau foundations.
• QNN.LieAlgebraicBP — the DLA-dimension → variance → barren-plateau chain.
• QNN.VarianceFormula — the Ragone reductive variance formula.
• QNN.FullDLABasis — the explicit su(2ⁿ) Hermitian basis and concrete exponential BP.
• QNN.PauliPropagation — Pauli-propagation truncation error.