General Linear Blend Frequency Polygon Density Estimation // Implements nonparametric density estimation with Averaged Shifted Histogram (ASH), Linear Blend Frequency Polygon (LBFP), and General Linear Blend Frequency Polygon (GLBFP) estimators. The package provides pointwise and grid-based estimation workflows, sparse-prefix grid-count computation, plotting helpers, and plug-in bandwidth selection. Methodological background follows Scott (1992) doi:10.1002/9780470316849, Terrell and Scott (1985) doi:10.1080/01621459.1985.10477163, and Carbon and Duchesne (2024) doi:10.1007/s10463-023-00883-5.