cluster0: compose overlays lab-seed shortener; fix workspace git safe.dir

Re-copy ShortLinksRepository from NFS seed after ac-ms-* overlays;
deploy-ac-workspace allows all safe.directory; verify-mail-lab logs short URL.

Co-authored-by: Cursor <cursoragent@cursor.com>

sim/cluster0/scripts/compose-lab-backend.sh

@@ -85,6 +85,17 @@ overlay_src ac-ms-tickets
 overlay_src ac-ms-graphs
 overlay_src ac-ms-remote-access
 
+# Lab-seed PHP not yet split into ac-ms-* repos — NFS seed stays authoritative after overlays.
+overlay_lab_seed_src() {
+  _f="$1"
+  if [ -f "${LEGACY}/src/${_f}" ]; then
+    log "overlay lab-seed src ${_f}"
+    cp -a "${LEGACY}/src/${_f}" "${COMPOSED}/src/"
+  fi
+}
+overlay_lab_seed_src ShortLinksRepository.php
+overlay_lab_seed_src UrlShortenerDatabase.php
+
 overlay_api ac-ms-identity
 overlay_api ac-ms-rbac
 overlay_api ac-ms-devices