Explain system dependencies in copilot-setup-steps.yml

Agent-Logs-Url: https://github.com/d-morrison/qwt/sessions/cc271470-4bcb-44f7-b99d-1f349eaceeb1

Co-authored-by: d-morrison <2474437+d-morrison@users.noreply.github.com>

Author: Copilot

.github/workflows/copilot-setup-steps.yml

@@ -43,7 +43,13 @@ jobs:
         with:
           submodules: true
 
-      # Install system dependencies required for R packages
+      # Install system dependencies needed for this project, including:
+      #
+      # - C/C++ libraries required by R packages (libcurl, libssl, libxml2, etc.)
+      # - PDF processing tools (poppler-utils) for working with PDF documents
+      # - OCR tools (tesseract-ocr) for optical character recognition tasks
+      # - A computer algebra system (maxima) for symbolic math computations
+      # - Python pip for additional tooling
       - name: Install system dependencies
         run: |
           sudo apt-get update