Optimize setup-workspace.sh and trigger CI on changes

1. Optimize `scripts/setup-workspace.sh` build time by enabling parallel builds (`-T 1C`) and skipping unnecessary Javadoc/Source generation.
2. Fix "Result: 128" git errors by explicitly disabling the `download-cn1-binaries` profile (`-P !download-cn1-binaries`).
3. Fix "Stubber.jar not found" build failure by explicitly passing `-Dcn1.binaries="$CN1_BINARIES"` to Maven commands, ensuring the external binaries are located.
4. Update `.github/workflows/pr.yml` to trigger the PR CI workflow when `scripts/setup-workspace.sh` is modified, enabling validation of these changes.

Author: google-labs-jules[bot]

scripts/setup-workspace.sh

@@ -233,13 +233,14 @@ log "Building Codename One Maven plugin"
   -pl codenameone-maven-plugin -am \
   -T 1C -Dmaven.javadoc.skip=true -Dmaven.source.skip=true \
   -DskipTests -Djava.awt.headless=true \
+  -Dcn1.binaries="$CN1_BINARIES" \
   -P !download-cn1-binaries \
   install "$@"
 
 BUILD_CLIENT="$HOME/.codenameone/CodeNameOneBuildClient.jar"
 log "Ensuring CodeNameOneBuildClient.jar is installed"
 if [ ! -f "$BUILD_CLIENT" ]; then
-  if ! "$MAVEN_HOME/bin/mvn" -f maven/pom.xml -P !download-cn1-binaries cn1:install-codenameone "$@"; then
+  if ! "$MAVEN_HOME/bin/mvn" -f maven/pom.xml -Dcn1.binaries="$CN1_BINARIES" -P !download-cn1-binaries cn1:install-codenameone "$@"; then
     log "Falling back to copying CodeNameOneBuildClient.jar"
     mkdir -p "$(dirname "$BUILD_CLIENT")"
     cp maven/CodeNameOneBuildClient.jar "$BUILD_CLIENT" || true