docs: route registrar skips through repo-manager

scripts/project_rules/first-session.template

@@ -29,6 +29,18 @@ C-06 creates the hub workplan + tasks and writes `state_hub_workstream_id`
 (legacy frontmatter name — holds the workplan UUID) and `state_hub_task_id`
 back into the file.
 
+If C-06/C-11 is skipped because the host is not the identifier registrar,
+commit and push the new workplan, then invoke the governed fallback once:
+
+```bash
+uv run --project ~/repo-manager rmgr registrar-reconcile \
+  --path . --confirm-primary --push
+```
+
+Never export `STATEHUB_REGISTRAR` or create the hub records manually. If the
+fallback is unavailable, send one request to `repo-manager` and keep working
+from the authoritative files.
+
 **Step 5 — Record the setup**
 ```
 add_progress_event(