Action implementations for the schedules tool — the boundary over YmerNode.Schedules.

The shape YmerNode.Mcp.Tools.Scripts.Actions takes: every extracted scalar is guarded on its head, and each guarded head is followed by a wrong-typed twin that answers a message rather than letting the context's own guard raise. args, lifetime and — on update — cron_expression are optional, so they are typed as they are taken, where a wrong one still has its key to name; a JSON null is taken as the key left out. What the values mean — a name's rule, a cron expression, a lifetime, args against the action's schema — the context judges, refusing each with a reason that names it.