Explicitly started supervisor for bounded managed execution.

Starting the library application alone opens no worker connections and starts no scheduler or database. A named runtime checks its host store semantics, then starts a bounded work subtree and an independent notification dispatcher. The work subtree couples its task supervisor and coordinator for recovery; a dispatcher restart alone does not interrupt those execution processes. Shutdown terminates observers; this is not proof of guest cancellation. Persisted due work is the restart authority. Durable mode never falls back to memory.