FixedPatchStepper.set_jet_amplitude validates index/amplitude and builds
the new rows before touching the device; invalid input leaves the
instance usable. A copy/sync error marks it failed (as initialize/step/
download do) and re-raises; host state (_jets, blocked velocity table)
commits only after a successful upload. CurvedLinkSoA.set_jet_amplitude
likewise uploads a new array first and commits jets/surface_velocity
afterwards. Focused mocked-driver tests for dense and blocked copy
failure, invalid input and IndexError.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>