Changes in version 0.2.0                        

  - motif_enrichment_stream(): enrichment over an Arrow stream of edges,
    with labels passed as a lookup keyed by integer node id. The
    network's nodes are the stream's endpoints. Needs smotifrs >= 0.2.0.

                        Changes in version 0.1.0                        

Initial scaffold of the smotif package for spatial multi-cellular motif
discovery in spatial omics data.

In scope for v0.1

  - SpatialGraph S3 class with parquet round-trip via arrow.
  - build_spatial_graph() over coordinates with kNN, Delaunay, and
    radius methods.
  - Motif enumeration (size 2 and 3 closed/open, size 4 via
    igraph::motifs) with colored canonical labeling for cell-typed
    nodes.
  - Spatially-aware null models: label permutation, region-stratified
    label permutation, geometric jitter.
  - Empirical enrichment testing with BH adjustment.
  - Wilcoxon and module-score gene association at motif and orbit level.
  - Cross-region and cross-sample motif comparison.
  - Reference dataset preparation script
    (inst/scripts/prepare_workshop_xenium.R) for the workshop Xenium
    human lung cancer FFPE slide.

Out of scope for v0.1 (planned later)

  - Rust / extendr backend (a # TODO(rust-backend) marker in R/motifs.R
    flags the dispatch site).
  - Motifs of size 5 or larger.
  - Directed motifs, hypergraphs, motif embeddings.
  - Per-sample meta-analysis in associate_genes().
  - Visualization beyond plot.Motifs().
  - Giotto Suite integration (intended as a separate downstream
    package).
  - Full geometric resampling null with re-thresholding.