Merge conformance report-path CWD fix

conformance/run.sh

@@ -137,8 +137,14 @@ run_chainsaw() {
 
   log "Running Chainsaw over ${#dirs[@]} test dir(s) with pinned ${CHAINSAW_VERSION}"
   # Chainsaw writes JUnit per config/chainsaw-config.yaml (report.* under _artifacts).
+  # --report-path is passed ABSOLUTE (overriding the config's relative `_artifacts`) so the report
+  # write succeeds regardless of the caller's CWD — otherwise chainsaw's relative path resolves
+  # against $PWD and fails ("open _artifacts/chainsaw-report.xml: no such file") when run.sh is
+  # invoked from the repo root instead of conformance/.
+  mkdir -p "${ARTIFACTS}"
   chainsaw test \
     --config "${CONF_ROOT}/config/chainsaw-config.yaml" \
+    --report-path "${ARTIFACTS}" \
     "${test_dir_args[@]}"
 
   # Normalize whatever chainsaw named the report to a stable path CI collects.