Add instance system guide nav (default off) with overview/options/hedge manual.

EOF

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

lib/common/static/instance_settings_prefs.js

@@ -20,7 +20,7 @@
   }
 
   /** 默认关闭的导航开关:缺失时按 false,不能用 !== false */
-  const NAV_DEFAULT_OFF = { show_nav_dashboard: true };
+  const NAV_DEFAULT_OFF = { show_nav_dashboard: true, show_nav_system_guide: true };
 
   function navPrefShow(display, key) {
     if (!key) return true;
@@ -41,6 +41,7 @@
       "hedge-plan": "show_nav_hedge_plan",
       hedge_plan: "show_nav_hedge_plan",
       risk_policy: "show_nav_risk_policy",
+      system_guide: "show_nav_system_guide",
       env_config: "show_nav_env_config",
     };
     document.querySelectorAll(".embed-top-nav [data-embed-tab], .top-nav a[href^='/']").forEach((a) => {
@@ -68,6 +69,7 @@
       "hedge-plan": "show_nav_hedge_plan",
       hedge_plan: "show_nav_hedge_plan",
       risk_policy: "show_nav_risk_policy",
+      system_guide: "show_nav_system_guide",
       env_config: "show_nav_env_config",
     };
     const key = map[tab];