feat: add conversation-scoped yolo controls

docs/PROTOCOL.md

@@ -292,6 +292,30 @@ clarifications accept free text.
 
 ---
 
+## Auto-approve (YOLO)
+
+YOLO is always conversation-scoped. It skips ordinary dangerous-command
+approval prompts for that Hermes session, while Hermes hard deny rules and
+hardline safety floors still apply.
+
+```json
+→ { "type": "yolo.current", "conversation_id": "a1b2…", "request_id": "r15" }
+← { "type": "yolo.snapshot", "enabled": false, "scope": "conversation",
+    "conversation_id": "a1b2…", "request_id": "r15" }
+
+→ { "type": "yolo.set", "conversation_id": "a1b2…", "enabled": true,
+    "request_id": "r16" }
+← { "type": "yolo.changed", "enabled": true, "scope": "conversation",
+    "conversation_id": "a1b2…", "request_id": "r16" }
+// plus broadcast of yolo.changed (without request_id) to all clients
+```
+
+`enabled` must be a JSON boolean. Unknown conversations return
+`conversation_not_found`. The adapter also persists the flag in Hermes session
+metadata so it can be restored after the gateway restarts.
+
+---
+
 ## Attachments (agent → client deliverables)
 
 When the agent produces a file (image, document, audio, video… via Hermes's