ci: install pandoc explicitly in docs workflow

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: mballance

.github/workflows/docs.yml

@@ -21,10 +21,11 @@ jobs:
       - name: Install Python dependencies
         run: pip install -r docs/requirements.txt
 
-      - name: Install LaTeX (for PDF generation)
+      - name: Install pandoc and LaTeX (for PDF generation)
         run: |
           sudo apt-get update -q
           sudo apt-get install -y \
+            pandoc \
             texlive-xetex \
             texlive-fonts-recommended \
             texlive-latex-extra