Fail early when renv packages are not synchronized after restore in CI (#14424)

When renv::restore() encounters network errors (e.g. package manager
returning HTTP errors), it can complete without failing even though some
packages were not properly installed. Downstream steps then fail with
cryptic errors like missing package functions.

Add renv::status() after restore and exit with status 1 if the library
is not synchronized with the lockfile, surfacing the failure at the
right point rather than later in the test run.

Author: cderv

.github/workflows/test-smokes.yml

@@ -175,6 +175,13 @@ jobs:
           cat("::group::Restoring R packages from renv.lock\n")
           renv::restore()
           cat("::endgroup::\n")
+          cat("::group::Verifying R packages are synchronized after restore\n")
+          status <- renv::status()
+          if (!isTRUE(status$synchronized)) {
+            cat("::error::R packages are not synchronized after restore - some packages may have failed to install\n")
+            quit(status = 1)
+          }
+          cat("::endgroup::\n")
           cat("::group::Installing dev versions of knitr and rmarkdown\n")
           # Install dev versions for our testing
           # Use r-universe to avoid github api calls