- Add IncrementalBuffer with thread-safe SendData/SendInitData callback
handling for live waveform plotting during transient simulations
- Expose get_incremental_data(), get_incremental_vector_names(),
get_incremental_count(), clear_incremental_buffer() to Python
- Add py::call_guard<py::gil_scoped_release>() on run(), run_async(),
SimRunner::run_now(), SimRunner::run() so Python UI stays responsive
- Update license from BSD-3-Clause to GPL-3.0-or-later (required by
GPLv3 components: admst, xspice/icm/table)
- Fix netlist preprocessor robustness when .end line is missing
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>