fix: revalidate authentication before bot start

docs/deployment.md

@@ -75,6 +75,12 @@ Success should distinguish:
 - no crash loop or new high-severity errors;
 - requested workload actually completed.
 
+The authentication lease deliberately expires while an account is idle. A
+start request revalidates the persisted Reddit and Matrix credentials before
+changing the run state, so an otherwise valid paused account does not become
+stuck behind the start safety gate. A failed revalidation still returns a
+conflict and requires a fresh extension session import.
+
 ## Account session operations
 
 The supported workflow is: