Packed fields and base flow

Owner for ingest: linstabpy.baseflow.grid_fields. Owner for BaseFlow: linstabpy.baseflow.

Eight keys

x, y, rho, u, v, w, T, sponge. YAML names the file. The loader does not guess a Song filename.

load_case_fields reads a directory of eight .npy files or one .npz with the same keys. After an optional transpose the arrays are (ny, nx). stride_eta walks the first index; stride_ksi walks the second.

Preprocess

Filter, boundary sponge, and shock cleanup live in baseflow.preprocess. Sponge generation (constant, parabolic, localized, smooth_boundary, smooth_localized) lives in baseflow.sponge. Viscosity in baseflow.viscosity.

Martini .mat constructors live under examples/martini/matlab_baseflow.py, not in this package path.