v0.12.0

Scale-and-honesty release on the 0.11 stack: Kronecker-sum exact spectrum
for eligible networked graph operators, and docs-only topology-criticality
honesty. Homogeneous scientific defaults and the linear latent operator
contract are unchanged.

Added

• Exact Kronecker-sum spectrum path for eligible discrete and continuous
  graph operators (koopman_graph.operators.kronecker_spectrum;
  GraphKoopmanOperator.spectrum /
  ContinuousGraphKoopmanOperator.spectrum). Eligibility requires a
  shared self factor, adjacency in {"symmetric", "random_walk"}, and
  sparsity in {"dense", "block_diagonal"}. Eigenvalues and ambient
  eigenvectors match the dense assembly oracle within float tolerance on
  path/ring fixtures.
• Three-path spectrum contract: distributed leading-modulus Arnoldi
  (discrete / multiplex hetero), Kronecker-sum exact reduction when
  eligible, otherwise dense assembly. Continuous distributed has no
  Arnoldi spectrum path and uses dense L_eff.
• Sphinx Scale / architecture / FAQ prose distinguishing the three
  spectrum paths and residual dense ceilings for exact inverse, Jacobi /
  Richardson, and eig-regularization hinges. Tutorial
  examples/29_large_graph_block_diagonal.ipynb records a dense vs
  Kronecker spectrum timing probe at the existing probe (N).
• Topology-criticality honesty in limitations (cross-linked from
  architecture / capabilities), with paper.bib entry Ghosh2025.
  Tutorial examples/18_networked_koopman_dynamic_topology.ipynb notes
  that dynamic topology remains mechanical (no spectral-degeneracy /
  early-warning diagnostic API).

Notes

• Kronecker reduction applies to spectrum only. Exact inverse /
  Jacobi / Richardson and eig-regularization hinges remain dense
  ((N\cdot d)) ceilings.
• No Kronecker-style spectrum for hetero / hypergraph ambient operators
  in this release.
• Homogeneous training defaults are unchanged relative to 0.11.0.

Full changelog: see CHANGELOG.md ([0.12.0] - 2026-08-05).