Add R package setup script for separate R installation

Create setup_r.sh to install required R packages (ggplot2, mgcv)
without requiring conda. Works with system R installations via
Homebrew, apt, or CRAN.

This allows using uv for Python dependencies while maintaining
R integration through rpy2 with a separate R installation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: tdhopper

setup_r.sh

@@ -0,0 +1,60 @@
+#!/bin/bash
+
+# Setup script for R and required R packages
+# This script installs the R packages needed for pythonplot.com
+
+set -e  # Exit on error
+
+echo "Installing R packages..."
+
+# Check if R is installed
+if ! command -v R &> /dev/null; then
+    echo "Error: R is not installed."
+    echo ""
+    echo "Please install R first:"
+    echo "  - macOS: brew install r"
+    echo "  - Ubuntu/Debian: sudo apt-get install r-base r-base-dev"
+    echo "  - Or download from: https://cran.r-project.org/"
+    exit 1
+fi
+
+echo "R version:"
+R --version | head -n 1
+
+# Install required R packages
+R --quiet --no-save << 'EOF'
+# Set CRAN mirror
+options(repos = c(CRAN = "https://cran.rstudio.com/"))
+
+# List of required packages
+packages <- c("ggplot2", "mgcv")
+
+# Install packages that aren't already installed
+for (pkg in packages) {
+    if (!require(pkg, character.only = TRUE, quietly = TRUE)) {
+        cat(paste("Installing", pkg, "...\n"))
+        install.packages(pkg, quiet = FALSE)
+    } else {
+        cat(paste(pkg, "is already installed\n"))
+    }
+}
+
+# Verify installations
+cat("\nVerifying R package installations:\n")
+for (pkg in packages) {
+    if (require(pkg, character.only = TRUE, quietly = TRUE)) {
+        cat(paste("✓", pkg, "version", as.character(packageVersion(pkg)), "\n"))
+    } else {
+        cat(paste("✗", pkg, "FAILED TO INSTALL\n"))
+        quit(status = 1)
+    }
+}
+
+cat("\n✓ All R packages installed successfully!\n")
+EOF
+
+echo ""
+echo "R setup complete!"
+echo ""
+echo "Note: If you encounter issues with rpy2, make sure R_HOME is set correctly:"
+echo "  export R_HOME=\$(R RHOME)"