fix(weixin): 扫码QR超时自动重发——修'二维码过期'(旧码被幂等返回)

StartLogin 幂等会一直返回同一二维码，但微信bot绑定码有效期极短；此前测试触发过一次登录
会话，旧码过了有效期,用户刷新仍拿到它→扫即'过期'。修: loginSession 加 startedAt,
超过 qrRefreshTTL(90s) 时 StartLogin 取消旧会话并重发新鲜二维码(panel'刷新二维码'永远可扫)。
重启清除内存中旧会话。build/test绿,已部署.

plugins/channels/weixin_ilink/login_admin.go

@@ -8,6 +8,7 @@ package weixin_ilink
 // concurrent QR binds.
 
 import (
+	"time"
 	"context"
 	"errors"
 	"fmt"
@@ -43,12 +44,18 @@ type LoginQR struct {
 type loginSession struct {
 	qrcode    string
 	image     string
+	startedAt time.Time
 	// cancel stops the poll goroutine early (e.g. Connect's deadline elapsed).
 	cancel context.CancelFunc
 	// done carries the login outcome; the poll goroutine writes exactly once.
 	done chan error
 }
 
+// qrRefreshTTL bounds how long a WeChat bot QR is usable before StartLogin re-mints
+// a fresh one. iLink bot QRs are short-lived; an idempotent StartLogin must not keep
+// serving a long-expired QR (the user would scan it and get "二维码过期").
+const qrRefreshTTL = 90 * time.Second
+
 // StartLogin begins a scan-login and returns the QR code to display. It is
 // idempotent: when a login is already in progress it returns the current QR
 // without issuing a new get_bot_qrcode, and when a bot token is already present it
@@ -63,8 +70,16 @@ func (a *Adapter) StartLogin(ctx context.Context) (LoginQR, error) {
 		return LoginQR{}, ErrAlreadyLoggedIn
 	}
 	if sess := a.loginSession; sess != nil {
+		// Idempotent for a fresh QR, but re-mint once the current QR has aged past
+		// qrRefreshTTL so the panel's 刷新二维码 always yields a scannable code.
+		if time.Since(sess.startedAt) < qrRefreshTTL {
 			return LoginQR{Qrcode: sess.qrcode, Image: sess.image}, nil
 		}
+		if sess.cancel != nil {
+			sess.cancel()
+		}
+		a.loginSession = nil
+	}
 
 	raw, err := a.fetchQRCode(ctx)
 	if err != nil {
@@ -76,6 +91,7 @@ func (a *Adapter) StartLogin(ctx context.Context) (LoginQR, error) {
 	sess := &loginSession{
 		qrcode:    raw.Qrcode,
 		image:     raw.QrcodeImgContent,
+		startedAt: time.Now(),
 		cancel:    cancel,
 		done:      make(chan error, 1),
 	}