Setup-scaling measurements for YAC 3.19.0

Wall-clock cost of YAC's coupling setup — distributed grid-pair generation, interpolation weight computation and internal setup — for two synthetic components on an icosahedral source grid and a cubed-sphere target grid. Measured on Levante (2× AMD EPYC 7763, InfiniBand HDR100) at 512 to 32,768 processes for four grid pairs (R02B08-C450, R02B09-C900, R02B10-C1800, R02B11-C3600) and three interpolation methods (4NN, first-order conservative, HCSBB), three repetitions each. The record contains the tidy dataset (data/timings.csv), the per-allocation provenance (data/runs.csv), the raw logs the dataset was parsed from (logs/), the scripts that produced both, and the figures generated from the dataset. Given the dataset alone, the figures can be regenerated with Python, PyYAML and matplotlib; reproducing the measurements themselves needs an allocation on Levante. Code is BSD-3-Clause, data, logs and figures are CC-BY-4.0.