refactor: 将共用代码迁入 lib/ 模块化目录

统一 strategy、key_monitor、trade、hub 等共用库到 lib/ 子包，并补充 lib-structure 文档，便于四所与中控维护。

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

lib/instance/instance_nav_lib.py

@@ -0,0 +1,19 @@
+"""中控 iframe 内软导航：服务端跳过重型同步，避免切 tab 等待数秒。"""
+
+from __future__ import annotations
+
+from flask import Request
+
+
+def request_is_hub_soft_nav(req: Request | None = None) -> bool:
+    """embed=1 且带 X-Instance-Soft-Nav 头：实例页内 fetch 换页，非整页刷新。"""
+    try:
+        from flask import request as flask_request
+
+        r = req or flask_request
+        if str(r.args.get("embed") or "").strip() != "1":
+            return False
+        flag = (r.headers.get("X-Instance-Soft-Nav") or "").strip().lower()
+        return flag in ("1", "true", "yes")
+    except Exception:
+        return False