fix: harden image handling and update docs

core/agent_tools.py

@@ -121,7 +121,9 @@ async def lookup_chat_history_tool(
             line = f"[{ts}] {role}：{msg}"
             lines.append(line)
             if r["direction"] == "in":
-                if "已收到" in msg and "图" in msg:
+                msg_type = int(r.get("msg_type") or 0)
+                image_urls = str(r.get("image_urls", "") or "").strip()
+                if msg_type == 1 or image_urls or ("已收到" in msg and "图" in msg):
                     has_images = True
                 if any(k in msg for k in ["找原图", "修复", "高清", "去背景", "抠图", "做衣服", "打印"]):
                     customer_needs.append(msg[:60])