Initial commit: BAF Lakehouse fraud detection pipeline

End-to-end LightGBM fraud detection pipeline built as an R package,
orchestrated by targets with data stored in MinIO via Apache Arrow.
Includes 6-layer Lakehouse architecture, class imbalance tournament,
formally tuned hyperparameters (PR-AUC 0.198), and Quarto RevealJS slides.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

man/plot_conf_mat_heatmap.Rd

@@ -0,0 +1,21 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/functions.R
+\name{plot_conf_mat_heatmap}
+\alias{plot_conf_mat_heatmap}
+\title{Plot Confusion Matrix Heatmap}
+\usage{
+plot_conf_mat_heatmap(cm, title = "")
+}
+\arguments{
+\item{cm}{A yardstick conf_mat object.}
+
+\item{title}{Character. The main title of the plot.}
+
+\item{subtitle}{Character. The subtitle of the plot.}
+}
+\value{
+A ggplot object.
+}
+\description{
+Generates a styled 4-quadrant heatmap from a yardstick confusion matrix.
+}