- FFT backend and pad factor persist across sessions via QSettings
(IniFormat; tests redirect the settings path for hermeticity).
- The default backend was labelled "NumPy FFT" but always dispatched to
scipy.fft — rename the canonical value to "scipy" ("numpy" stays as a
legacy alias) and fix the dialog label.
- cache_file: DC caching fans out over angles via _parallel_map with
per-angle budgets (the DcPrecomputeWorker pattern); FFT caching stays
serial per angle because compute_rf_image now parallelises internally
over blocks. Documented that the v7 FFT cache is natural-resolution
(pad 1) by design.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Thomas Ales
9a9a2557d6