v0.8.3

What's Changed

Documentation — all seven vignettes expanded from brief overviews
(2,195 words total) into full worked guides (27,830 words): quickstart,
diversity, rarefaction/standardization, community assembly, spatial analysis,
extrapolation, and richness estimation. Each now covers the underlying model,
simulation with known ground truth, fitting, uncertainty,
prediction/comparison, and practical guidance, and exercises the full exported
API (including evenness(), diversityProfile(),
spatialEigenvectors()/spatialPartition(), wavefront(), and
compareModels()).

Submitted to CRAN (first submission). win-builder r-devel + r-release and local
R CMD check --as-cran: 0 errors, 0 warnings, 1 NOTE (new submission).