feat: heal dead sync channels and block deleting system default (Z12h)

Ensure default channel and rebind Agent/Binding on list, ticket, agents/me, and ensure-binding so SyncPage does not stay on deleted-channel errors.

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

platform/internal/handler/sync.go

@@ -9,6 +9,7 @@ import (
 	"aijianzhan/platform/internal/audit"
 	"aijianzhan/platform/internal/authx"
 	"aijianzhan/platform/internal/dbsync"
+	"aijianzhan/platform/internal/logic/applogic"
 	"aijianzhan/platform/internal/svc"
 
 	"github.com/zeromicro/go-zero/rest/httpx"
@@ -41,7 +42,12 @@ func syncListHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
 		if !requireDBSync(svcCtx, w) {
 			return
 		}
-		list, err := svcCtx.DBSync.Store().ListChannelsByTenant(syncTenantID(r))
+		tid := syncTenantID(r)
+		if _, err := applogic.HealTenantSyncBind(r.Context(), svcCtx, tid); err != nil {
+			// 列表仍继续，避免自愈失败挡运维
+			_ = err
+		}
+		list, err := svcCtx.DBSync.Store().ListChannelsByTenant(tid)
 		if err != nil {
 			authx.WriteError(w, http.StatusBadRequest, err.Error())
 			return
@@ -109,15 +115,26 @@ func syncDeleteHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
 			return
 		}
 		id := pathvar.Vars(r)["id"]
-		if _, err := svcCtx.DBSync.Store().GetChannelForTenant(id, syncTenantID(r)); err != nil {
+		tid := syncTenantID(r)
+		ch, err := svcCtx.DBSync.Store().GetChannelForTenant(id, tid)
+		if err != nil {
 			authx.WriteError(w, http.StatusNotFound, err.Error())
 			return
 		}
+		// Z12h-1：公司默认同步通道禁止删除（账号落点依赖它）
+		if ch.IsSystemDefault {
+			authx.WriteError(w, http.StatusBadRequest, "公司默认同步通道不可删除；账号绑定落点依赖此通道。若异常请刷新页面自动修复")
+			return
+		}
 		svcCtx.DBSync.StopChannel(id)
 		if err := svcCtx.DBSync.Store().DeleteChannel(id); err != nil {
 			authx.WriteError(w, http.StatusBadRequest, err.Error())
 			return
 		}
+		// 若误删后仍有 Binding 挂死，heal 会挂回默认通道
+		if _, hErr := applogic.HealTenantSyncBind(r.Context(), svcCtx, tid); hErr != nil {
+			_ = hErr
+		}
 		httpx.OkJson(w, map[string]any{"ok": true})
 	}
 }