Auto-reconnect CTP with new front-end addresses after saving settings

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

app.py

@@ -1715,20 +1715,26 @@ def settings():
             from ctp_settings import save_ctp_settings_from_form
 
             save_ctp_settings_from_form(request.form, set_setting)
+            flash_msg = "CTP 配置已保存，正在使用新地址重连…"
             try:
-                from vnpy_bridge import get_bridge, _persist_last_error
+                from vnpy_bridge import get_bridge
+                from trading_context import get_trading_mode
 
                 b = get_bridge()
-                b.mark_disconnected()
                 if (request.form.get("simnow_password") or "").strip() or (
                     request.form.get("ctp_live_password") or ""
                 ).strip():
                     b._clear_login_cooldown()
-                    b._last_error = ""
-                    _persist_last_error("")
-            except Exception:
-                pass
-            flash("CTP 配置已保存，请在持仓监控页重连 CTP")
+                mode = get_trading_mode(get_setting)
+                info = b.reconnect_after_settings_saved(mode)
+                if info.get("cooldown"):
+                    flash_msg = "CTP 配置已保存；当前处于登录冷却，请稍后再连"
+                elif not info.get("started") and info.get("connected"):
+                    flash_msg = "CTP 配置已保存，当前连接正常"
+            except Exception as exc:
+                app.logger.warning("CTP reconnect after settings save: %s", exc)
+                flash_msg = "CTP 配置已保存，请稍后在持仓监控页重连"
+            flash(flash_msg)
         elif action == "nav":
             items = {k: request.form.get(f"nav_{k}") == "on" for k in NAV_TOGGLES}
             save_nav_items(set_setting, items)