[ENH] API to work with LSL

[qian-chu]

Inspired by conversations I had during I-MOVE 2025. While LSL offers a stable way to synchronize Neon with other devices, only gaze data points and some optional events are streamed to LSL. It will be of interest, for example, to have functionalities mapping Neon UTC timestamps to the time reference system in LSL (XDF files).

First, a few details need to be investigated:

• The format of streamed Neon data in LSL XDF outputs
• Is there additional drift during the transmission? (e.g., could two samples that are 5 ms apart in Neon be spaced nearer/farther in XDF, given LSL dynamically estimates round-trip times). If so, how to handle this blocked temporal synchrony?