fix(pheby): restore paged history across session resets

docs/PROTOCOL.md

@@ -99,6 +99,7 @@ Limits: chat text ≤ 64,000 chars; inbound WS frame ≤ 2 MiB (violations get
     "messages": [
       { "message_id": "m12", "role": "user",      "text": "hey",  "ts": "…|null" },
       { "message_id": "m13", "role": "assistant", "text": "hi!",  "ts": "…|null" } ],
+    "has_more": true,
     "attachments": [],
     "run": null,
     "tools": [],
@@ -107,7 +108,12 @@ Limits: chat text ≤ 64,000 chars; inbound WS frame ≤ 2 MiB (violations get
 ```
 
 History is the authoritative Hermes transcript (`role` is always `user` or
-`assistant`). The other fields form a recoverable snapshot: unexpired
+`assistant`). It spans all durable reset and compression generations sharing
+the Pheby conversation key. `limit` is capped at 500; the response returns the
+newest page in chronological order. While `has_more` is true, request earlier
+pages with `"before_message_id": "m12"`, using the first message ID from the
+previous page as an exclusive cursor. This is display history only; model
+context can still be compressed. The other fields form a recoverable snapshot: unexpired
 attachments, the active run (if any), latest structured tool states, and
 pending approval/clarification requests. On reconnect, replace local state
 with this snapshot, then consume new live events. Unknown conversation →