Add gap_tolerance_ms API to Neuralynx reader

[h-mayorquin]

Adds the gap_tolerance_ms parameter to NeuralynxRawIO and NeuralynxIO, following the pattern established by the Blackrock reader in #1789. When gaps are detected and no tolerance is set, a ValueError is raised with a detailed gap report. When a tolerance is provided, the data is automatically segmented at gaps exceeding that threshold. The old strict_gap_mode parameter is deprecated with a warning. By default (gap_tolerance_ms=None), only gaps of at least one sample period are reported as errors; sub-sample timestamp deviations from rounding or clock jitter are silently ignored.

A _get_neuralynx_timestamps() method exposes the original per-record hardware timestamps in microseconds, giving users access to the raw timing information for drift analysis or precise alignment with external systems.

The test infrastructure gains rawio_kwargs on BaseTestRawIO and io_kwargs on BaseTestIO, allowing any format's tests to pass constructor arguments without overriding test methods or subclassing the IO class.

[samuelgarcia]

This is heroic!
I will try to have a look soon ! ( i am a lier )