a5R 0.4.0

• a5_grid() is soft-deprecated in favour of a5_polygon_to_cells().
  Calling it now emits a lifecycle::deprecate_warn() with guidance: use
  a5_polygon_to_cells() for geometry inputs (centre-in-polygon
  containment), or pass a wk::rct() bounding box for the bbox use
  case. Note that the two functions are not semantically identical:
  a5_grid() uses boundary intersection (any cell touched by the
  geometry), whereas a5_polygon_to_cells() uses centre-point
  containment (cells whose centroid lies inside).
• New a5_polygon_to_cells() returns the A5 cells whose centres lie
  inside a polygon. Distinct from a5_grid(), which uses
  boundary-intersection semantics. Accepts wk-handleable geometries
  (including MULTIPOLYGON and sfc of several polygons), terra
  SpatVector objects, numeric matrices, or data.frame(lon, lat).
  Multi-part inputs are handled natively: per polygon part the outer
  ring's cells are computed and any hole-ring cells are subtracted,
  then the results are unioned across parts and recompacted.
• New a5_linestring_to_cells() returns the A5 cells whose pentagons
  are intersected by a great-circle polyline, in discovery order along
  the path. Accepts the same input shapes as a5_polygon_to_cells(),
  including MULTILINESTRING, sfcs of multiple linestrings, and
  terra SpatVector objects; per-feature outputs are concatenated
  with first-seen deduplication.
• Bumped the embedded a5 Rust crate from 0.7.0 to 0.8.0. Transparent
  improvements inherited from upstream: resolution-30 (de)serialisation
  (a5 0.7.1), neighbour functions at resolutions 0 and 1 (a5 0.7.2),
  longitude normalisation in cell_to_lonlat (a5 0.7.3), faster
  cell_to_parent, and a polar-region spiral fix in grid_disk and
  spherical_cap.
• Breaking: a5_cell_to_lonlat() replaces its normalise argument
  with as_dataframe (default FALSE). When FALSE, centroids are
  returned as a wk::xy() vector with WGS 84 CRS; when TRUE, as a
  base data.frame with lon/lat columns. The previous normalise
  argument toggled longitude normalisation, but upstream a5 (>= 0.7.3)
  always returns normalised longitudes, so the flag's effective job
  collapsed to "what container?". as_dataframe makes that explicit.
  Defaults are unchanged for users who never set normalise (still
  returns wk::xy); explicit normalise = TRUE/FALSE calls now
  error and must be updated.
• New lifecycle dependency added to Imports.

a5R 0.3.1

• a5_cell() now requires hex strings to be exactly 16 characters,
  preventing silent construction of wrong cells from truncated input.
• Improved vignettes covering the new a5_cell representation and Arrow
  integration.
• a5_cell internal representation now uses 8 parallel raw byte vectors
  instead of hex strings, reducing memory from ~80 bytes/cell to 8
  bytes/cell (#12).
• a5_cell gains vec_proxy_compare() and vec_proxy_order() methods,
  enabling sort(), order(), unique(), duplicated(), match(),
  and %in% (#12).
• a5_cell gains an is.na() method (#12).
• New a5_cell_from_arrow() and a5_cell_to_arrow() for lossless
  conversion between a5_cell and Arrow uint64 arrays, enabling
  zero-copy Parquet I/O (#12).
• New a5_u64_to_hex() and a5_hex_to_u64() for explicit conversion
  between a5_cell vectors and hex strings.
• a5_is_cell() has been renamed to a5_is_valid() and now accepts
  both a5_cell vectors and character hex strings.
• a5_cell_distance() and a5_cell_area() gain a units = NULL
  option to return plain numeric vectors without units class
  overhead.
• New vignettes: vignette("internal-cell-representation") and
  vignette("arrow-parquet").

a5R 0.2.0

Initial CRAN release.