Install pak into system library

Dockerfile

@@ -66,7 +66,10 @@ RUN curl -L https://rig.r-pkg.org/deb/rig.gpg -o /etc/apt/trusted.gpg.d/rig.gpg
 
 # Because $HOME gets masked by GHA with the host $HOME
 ENV R_LIBS_USER=/opt/R/current/lib/R/site-library
-RUN rig add 4.4.0
+# Don't install pak. Rig installs it into the user lib, but we want it in the system lib
+RUN rig add 4.4.0 --without-pak
+# Install pak into the system lib
+RUN /opt/R/current/bin/R -q -e 'install.packages("pak", lib = .Library)'
 
 # Download webR and configure for LLVM flang
 RUN git clone https://github.com/r-wasm/webr.git /opt/webr