The automation bridge inherited two master-era assumptions the message
machine no longer honors. A prompt blocked at pre-turn admission opens no
turn, so no turn/end could ever settle it — the bridge now watches
whenIdle() and reports a turnless slot as cancelled (the disposed-agent
guard moved to a registry identity check before send). A failed turn no
longer rejects at its turn/end either: agent.retry() closes the failed
turn and opens a successor on the same history, so the bridge holds the
terminal error and lets a retry-triggered turn/start adopt the prompt,
rejecting only at quiescence with no successor.
Also: refresh the empty-response-retry fixture for retry-as-turn logging,
adapt master-side tests to the unified send()/UserMessageData API and
registry-fact disposal, resync the doc pairs both sides touched, trim
architecture.md back under its word ceiling, and regenerate the event and
persistence catalogs.