- Added `_decode_a5_waveform()` to parse SUB 5A frames into per-channel time-series data.
- Introduced `download_waveform(event)` method in `MiniMateClient` to fetch full waveform data.
- Updated `Event` model to include new fields: `total_samples`, `pretrig_samples`, `rectime_seconds`, and `_waveform_key`.
- Enhanced documentation in `CHANGELOG.md` and `instantel_protocol_reference.md` to reflect new features and confirmed protocol details.
