- Added `#subscriberEmitGate: Promise<void>` FIFO ticket to order concurrent `#emitSessionEvent` calls and prevent event reordering.
- Modified `#emitSessionEvent` to serialize subscriber fan-out: waits for previous gate before emitting, ensuring `message_start` arrives before `message_end` regardless of extension handler asymmetry.
- Added `#prunedTerminalRefusal` field to retain classifier-refusal turns for post-settle readers.
