Fix Quarto CI R dependencies

Author: Copilot

.github/workflows/preview.yml

@@ -22,15 +22,16 @@ jobs:
         uses: quarto-dev/quarto-actions/setup@v2
 
       - name: Setup R
-        if: ${{ !github.event.pull_request.head.repo.fork }}
         uses: r-lib/actions/setup-r@v2
 
-      - name: Render (trusted PRs)
-        if: ${{ !github.event.pull_request.head.repo.fork }}
-        run: quarto render .
+      - name: Setup R dependencies
+        uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: |
+            any::knitr
+            any::rmarkdown
 
-      - name: Render (fork PRs without execution)
-        if: ${{ github.event.pull_request.head.repo.fork }}
+      - name: Render
         run: quarto render . --execute false
 
       - name: Deploy PR Preview

.github/workflows/publish.yaml

@@ -21,8 +21,15 @@ jobs:
       - name: Setup R
         uses: r-lib/actions/setup-r@v2
 
+      - name: Setup R dependencies
+        uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: |
+            any::knitr
+            any::rmarkdown
+
       - name: Render Quarto
-        run: quarto render .
+        run: quarto render . --execute false
 
       - name: Deploy 🚀
         uses: JamesIves/github-pages-deploy-action@v4

README.md

@@ -52,7 +52,7 @@ All members of the Strategy Unit organisation on Github should be able to contri
 
 ### Potential issues
 
-The GitHub action runner does not have R installed on it, so as mentioned above, all computations must be run locally and then added to the _freeze folder.
+The GitHub action installs a minimal R setup so Quarto can render pages that rely on `knitr`/`rmarkdown`, but the workflows still render with `--execute false`. As mentioned above, all computations must still be run locally and then added to the `_freeze` folder.
 
 #### code-fold blocks