holoviz/datashader: Version 0.19.0

This release brings band-wise 2D support to quadmesh, several QuadMesh bug fixes, significant performance improvements to colorize and QuadMesh mesh operations, removal of the CLI, and compatibility updates for Pandas 3.0, Python 3.14, and cuDF 26.02. Thanks to first time contributor @dcherian, and regular contributors @Azaya89, @philippjfr, and @hoxbro. Features: Make quadmesh support band-wise 2D (#1472) Breaking Changes: Remove the CLI interface which been broken since version 0.17.0 (#1484) Deprecate copy_examples, fetch_data and examples with expected removal in version 0.20.0 (#1462) Bug Fixes: Support dask.array without dask.dataframe (#1454) Improve compute_chunksize for downsampled data (#1448) Handle descending coordinates in QuadMeshRaster downsampling (#1441) Propagate NotImplementedError for mode (#1436) Fix bug in QuadMeshRectilinear (#1459) Fix rendering viewport fully contained in one cell (#1442) Performance: Reorder loops in QuadMeshCurvilinear (#1449) Interval bounds updates (#1446) Use more inplace operations in quadmesh (#1444) Use numba for faster estimation of QuadMeshCurvilinear bounds (#1443) Optimize colorize using matrix multiplication, inplace operations, and float32 conversion (#1437) Compatibility: Pandas 3.0 (#1473, #1474, #1480) Python 3.14 (#1466) cuDF 26.02 (#1434, #1464, #1471, #1478) Tests: Refactor slow tests to run better in parallel (#1468) Add benchmark to CI (#1450, #1451, #1453, #1455, #1457, #1476) Maintenance: Reduce size of assets/images (#1479) Replace direct download of NYC Taxi with hvsampledata (#1462)