agriME 0.1.0

• Initial release.
• Added price-spread, producer-share, marketing-margin, and consumer-rupee decomposition tools.
• Added conventional, Shepherd, and Acharya marketing-efficiency measures.
• Added stage-level marketing-channel validation and accounting diagnostics.
• Added channel ranking, bootstrap confidence intervals, sensitivity analysis, efficiency target calculations, and loss-adjusted margins.
• Added two illustrative agricultural marketing datasets, a vignette, base R plots, executable examples, and regression tests.