deploy: gate the port wait after stopping this service's own quadlet

A redeploy of a running frank-large holds 7770 itself, so waiting on the port
before stopping the unit would have made every subsequent deploy fail. Stop the
user unit first (a no-op on a first cutover), then wait, then install and start.

scripts/deploy-remote.sh

@@ -1023,6 +1023,10 @@ wait_port_free() {
 
 deploy_llm_large() {
     retire_root_llm_large
+    # The predecessor can also be THIS quadlet -- a redeploy of a running
+    # frank-large -- so stop the user unit before waiting on the port. On a
+    # first cutover it is not running and this is a no-op.
+    systemctl --user stop frank-large.service 2>/dev/null || true
     # Pull once, then run the localhost/-aliased tag: this host's quadlet path
     # cannot resolve registry-prefixed refs from local storage at create time
     # (same workaround as anubis/hermes), and Pull=never keeps boots off the