fix(weixin): 扫码登录端点兼容裸weixin适配器——accountId不再404

weixin 适配器可能注册为裸 `weixin-ilink`(单账号)而非 `weixin-ilink:<acct>`, weixinAccountFor
只认复合名导致 accountId=05487->404。修为: 按平台匹配 + 优先复合名 + 找不到时兜底用裸
weixin 适配器(面板传config账号id)。实测 accountId=05487 登录端点 200{idle}。build/test绿。

internal/services/gateway/admin_channels_weixin.go

@@ -174,6 +174,12 @@ func weixinAccountFor(caps CapabilityStore, platform, accountID string) (weixinL
 	if caps == nil {
 		return nil, false
 	}
+	// A weixin adapter may be registered with the bare "weixin-ilink" name (single
+	// account) rather than "weixin-ilink:<acct>", so first try a composite match, and
+	// fall back to a bare weixin adapter when the caller names a specific account but
+	// no composite name carries it (the panel passes the config account id).
+	var bare weixinLoginAdmin
+	var bareFound bool
 	for _, cap := range caps.List(capreg.KindChannel) {
 		ch, ok := cap.Value.(sdk.Channel)
 		if !ok {
@@ -183,12 +189,19 @@ func weixinAccountFor(caps CapabilityStore, platform, accountID string) (weixinL
 		if plat != platform {
 			continue
 		}
-		if accountID != "" && acct != accountID {
+		w, ok := asWeixinLoginAdmin(cap.Value)
+		if !ok {
 			continue
 		}
-		if w, ok := asWeixinLoginAdmin(cap.Value); ok {
+		if accountID == "" || acct == accountID {
 			return w, true
 		}
+		if acct == "" {
+			bare, bareFound = w, true
+		}
+	}
+	if bareFound {
+		return bare, true
 	}
 	return nil, false
 }