recompute welch timestamp , taking middle instead of start of spectro_duration or tuiles

[cazaudo]

in https://github.com/Project-OSmOSE/OSEkit/blob/main/src/OSmOSE/Spectrogram.py , we need to revise the definiton of list_timestamps , currently defined as

            list_timestamps.append(
                current_timestamp + timedelta(seconds=int(start))
            )

should be defined as the middle value of the wav (or the tuile if self.zoom_level>0) time boundaries

[Gautzilla]

I didn't see this issue, sorry!

If i'm not mistaken, it just centers the time values on the tuiles instead of marking their start?

We have the tile_duration in this scope, and thus could use it directly?

        for tile in range(nber_tiles_lowest_zoom_level):
            start = tile * tile_duration
            end = start + tile_duration

            if not adjust:
                list_timestamps.append(
                    current_timestamp + timedelta(seconds=int(start + tile_duration//2)),
                )
            )

I've not tested it yet, that just to clarify that I understand correctly the issue!