Add QR pairing (terminal QR, in-app scanner, iris://pair deep link)

docs/diagrams/architecture.mmd

@@ -17,7 +17,7 @@ flowchart TB
             WSS["WebSocket SERVER<br/>(websockets) ws://host:8790/ws"]
         end
         AGENT -->|legacy stream callbacks| ADAPTER
-        CRON -->|deliver=android:chat:thread| ADAPTER
+        CRON -->|deliver=iris:chat:thread| ADAPTER
         ADAPTER <--> WSS
         ADAPTER <--> OUTBOX
         ADAPTER <--> PUSH