feat(hub): rolling chat summary to cap AI context and prevent mid-session failures

Co-authored-by: Cursor <cursoragent@cursor.com>

manual_trading_hub/hub_ai/text_util.py

@@ -0,0 +1,14 @@
+"""中控 AI 文本小工具。"""
+
+
+def is_ai_error_reply(text: str) -> bool:
+    t = (text or "").strip()
+    return t.startswith("AI 调用失败") or t.startswith("AI 生成失败")
+
+
+def clip_text(text: str, max_chars: int) -> str:
+    s = str(text or "").strip()
+    limit = max(200, int(max_chars or 0))
+    if len(s) <= limit:
+        return s
+    return s[: limit - 1].rstrip() + "…"