Prototype correlated lifecycle events for streaming sessions

Description

Prototype stage events across streaming session connection and disconnection paths so operators can reconstruct a session lifecycle and identify the component or stage where setup or teardown failed.

Definition of Done

• Each participating connection and disconnection stage emits a lifecycle event.
• Events include a shared session or request identifier, stage, outcome, and timestamp.
• Events from one session can be correlated and ordered across participating components.
• Failed or timed-out stages retain enough context to identify where the session stopped progressing.
• The event schema and destination are documented before the prototype is promoted to a supported interface.