[SChristineP]

Main changes:
plots.plot_diana_spectrum():

• Mean direction arrows for swell and wind sea waves are now derived by aggregating spectra prior to partitioning, rather than averaging directions from individually partitioned spectra, so the arrows reflect the plotted aggregated spectrum.
• Added an option to plot mean peak wave, swell, and wind sea directions, in addition to the existing mean wave, swell, wind sea, and wind directions.

plots.plot_partition_peak_dir_freq_2d()

• Added a new function that generates 2D direction–frequency polar plots, showing the number of occurrences of peak direction–frequency pairs for wind sea and swell waves.

filter_period()

• Changed the period input type from a tuple to a list.
• Increased flexibility by allowing partial specifications (e.g. providing only the year).

integrated_parameters()

• Removed this function, as the spectral functions now rely on integrated_parameters_dict() instead.