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>

_pkgdown.yml

@@ -0,0 +1,57 @@
+url: https://docs.robwiederstein.org/baflakehouse
+
+template:
+  bootstrap: 5
+  bootswatch: flatly # Clean, professional look
+
+navbar:
+  structure:
+    left: [intro, reference, articles, presentation]
+  components:
+    presentation:
+      text: "Slides"
+      icon: fa-person-chalkboard
+      href: slides/index.html
+
+reference:
+  - title: "Data Ingestion & Lakehouse Setup"
+    desc: "Functions for moving data from CSV to partitioned Parquet in MinIO."
+    contents:
+      - baflakehouse-package
+      - convert_to_parquet
+      - connect_baf
+      - clean_baf_base
+      
+  - title: "Feature Engineering & Preprocessing"
+    desc: "The 'Recipes' layer of the pipeline."
+    contents:
+      - engineer_features
+      - prepare_eda_recipe
+      - build_baf_recipe          # NEW: Untrained blueprint for production
+      - generate_model_inputs
+
+  - title: "The Tournament (Model Selection)"
+    desc: "Cross-validation and imbalance strategy testing."
+    contents:
+      - run_imbalance_tournament
+      - train_diag_model
+      - create_efficiency_plot    # Moved here: Belongs with the tournament
+
+  - title: "Final Evaluation & Production Deployment"
+    desc: "Results on unseen data (Months 6-7) and MinIO artifact serialization."
+    contents:
+      - evaluate_final_model
+      - train_production_model    # NEW: The final deployment function
+
+  - title: "Reporting: Tables & Visualizations"
+    desc: "Generating ggplot2 figures and gt tables for Quarto."
+    contents:
+      - starts_with("plot_")
+      - starts_with("compute_")
+      - starts_with("format_")    # Neatly catches all your gt table formatters
+
+  - title: "Pipeline Utilities"
+    desc: "Internal helpers for the targets workflow and slide generation."
+    contents:
+      - starts_with("save_report_")
+      - render_slides             # Consolidated here