Document and demonstrate execution controls

docs/internal/observation.md

@@ -14,6 +14,9 @@ The public projection retains private operation-owner metadata separately from
 inspectable child causes. Terminal classification uses that owner, preserving
 context precedence and generation-specific transport/provider details rather
 than mistaking a collaborator's nested lookup error for the parent's operation.
+Timeout attribution is finalized and the child scope released before terminal
+delivery, so observer latency cannot change the already selected outcome.
+Prepared-content notification is a separate opt-in callback, not an event.
 
 The facade masks inherited recorder and prepared-claim state when entering
 preparation or execution. Delegated calls from an injected collaborator retain