ci: symlink /work -> GITHUB_WORKSPACE for ks %post SRC probe

.github/workflows/build-iso.yml

@@ -100,6 +100,12 @@ jobs:
           ksvalidator kickstart/veilor-os-ci.ks
           mkdir -p build/out
 
+          # The kickstart's %post --nochroot probes a fixed list of
+          # candidate paths to locate the repo source for overlay/scripts
+          # copy. /work is the canonical CI candidate; symlink the live
+          # workspace there so the existing probe finds it.
+          ln -sfn "$GITHUB_WORKSPACE" /work
+
           mkdir -p /var/lmc /var/lmc-cache
           livecd-creator \
             --verbose \