Biopsykit

Internal Changes
- Migrated from `poetry` to `uv` as the main build tool. This change is due to the fact that `uv` is more flexible and
allows for more customization. The `pyproject.toml` file was updated accordingly.

Bugfix
- small bugfixes in PEP Algorithms and Biopac importer (improved error handling)

Bugfix
- Updated `pandas` version constraint from "^1" to "^2" and updated all code and test cases to be compatible with newer
`pandas` versions.

New Features
- Added new algorithms for pre-ejection period (PEP) computation in `biopsykit.signals`, including
algorithms for ECG Q-peak extraction (`biopsykit.signals.ecg`) and ICG B-point extraction (`biopsykit.signals.icg`).
Added further utility functions (e.g., for heartbeat segmentation) and to compute the PEP using a combination
of ECG and ICG data (`biopsykit.signals.pep`).

Changes
- Made `biopsykit` compatible with matplotlib >= 3.9.

Changes
- `BaseProtocol.add_salvia_data` now also accepts absolute saliva sample times as argument
by setting `sample_times_absolute=True`.
- `bp.protocols.plotting.saliva_plot`: removed hardcoded number of plotting colors (2) when plotting data with
multiple conditions (> 2)