feat(weixin-ilink,gateway): 会话过期显式化 — 不再静默变哑/假 OK 重连，面板可见「需重扫」

- 适配器新增过期状态机(plugins/channels/weixin_ilink/session_state.go)：getupdates/sendmessage/getuploadurl 收到 errcode=-14 即 markExpired（ERROR 仅一次，只带 bot_id，token 永不入日志），扫码登录拿到新 token 或配置换新 token 时清除（惰性比对）
- Connect/HealthCheck 在过期时返回 ErrSessionExpired（可与 ErrNotConnected 区分）：不再对死 token 设 connected=true 报假成功；发送路径同样返回该错误而不是笼统 ErrNotConnected
- 网关：POST /admin/channels/open 遇过期 → 409 session_expired + 明确文案（不再吞错回 200）；GET /admin/channels 摘要新增 needsRescan/lastError（经可选接口类型断言读取，取不到不伪造）
- channelbridge：读循环非取消退出时把自身记账的 connected 置 false（热重载被替换者退出不抹掉新实例）
- login/login_admin：过期时 StartLogin 允许重新出码、LoginStatus 如实报 failed（原先可能把死 token 当 confirmed 重新落盘）
- Docs/api-client v0.39；新增 5 组测试 + 变异验证（去掉标记/恢复假成功/网关不填字段 均 FAIL）

internal/services/gateway/admin.go

@@ -34,10 +34,16 @@ type PluginSummary struct {
 // carries that platform's configured accounts (masked, no raw tokens) so the
 // panel can show and edit the account config; it is omitted when s.channels is
 // not wired or the platform has no configured account.
+//
+// NeedsRescan/LastError (v0.39) report that the adapter needs the owner to
+// re-authorize it (see rescanAware in admin_channels_rescan.go); both are omitted
+// unless the adapter really asked for it.
 type ChannelSummary struct {
-	Name      string                `json:"name"`
-	Connected bool                  `json:"connected"`
-	Accounts  []AdminChannelAccount `json:"accounts,omitempty"`
+	Name        string                `json:"name"`
+	Connected   bool                  `json:"connected"`
+	NeedsRescan bool                  `json:"needsRescan,omitempty"`
+	LastError   string                `json:"lastError,omitempty"`
+	Accounts    []AdminChannelAccount `json:"accounts,omitempty"`
 }
 
 // policyRequest is the POST /api/v1/admin/plugins/policy body.
@@ -172,6 +178,15 @@ func (s *Server) adminListChannels(w http.ResponseWriter, r *http.Request) {
 				continue
 			}
 			sum := ChannelSummary{Name: platform, Connected: ch.IsConnected()}
+			// Optional rescan capability (weixin-iLink expired token, v0.39): reported
+			// only when the adapter really asks for a re-scan, so a healthy adapter
+			// keeps the fields omitted rather than shipping a fabricated value.
+			if ra, ok := asRescanAware(cap.Value); ok {
+				if required, reason := ra.RescanRequired(); required {
+					sum.NeedsRescan = true
+					sum.LastError = reason
+				}
+			}
 			if accts, ok := accountsByPlatform[platform]; ok && len(accts) > 0 {
 				sum.Accounts = enrichAccountsWithBot(accts, botByPlatform[platform])
 			}