docs: 更新协议文档，删除废弃计划文档

- 更新 http-error-codes, user-points-chat-data-protocol
- 更新 divination-run-protocol, profile-protocol
- 删除废弃的后端和前端设计计划文档

backend/tests/unit/test_history_message_schema.py

@@ -0,0 +1,29 @@
+from __future__ import annotations
+
+from v1.agent.schemas import HistoryMessage
+
+
+def test_history_message_accepts_follow_up_error_payload() -> None:
+    payload = {
+        "id": "msg-1",
+        "threadId": "thread-1",
+        "seq": 2,
+        "role": "assistant",
+        "content": "补充回答",
+        "timestamp": "2026-04-08T07:31:24+00:00",
+        "agent_output": {
+            "status": "failed",
+            "answer": "需要补充信息",
+            "error": {
+                "code": "INVALID_INPUT",
+                "message": "输入内容不完整",
+                "retryable": True,
+                "details": {},
+            },
+        },
+    }
+
+    parsed = HistoryMessage.model_validate(payload)
+    assert parsed.agent_output is not None
+    assert parsed.agent_output.error is not None
+    assert parsed.agent_output.error.code == "INVALID_INPUT"