fix: allow deleting system default sync channel with immediate heal

Remove hard ban that returned 400 with no UI feedback; delete then Ensure+rebinding, and show confirm/toast on SyncPage.

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

web/src/SyncPage.tsx

@@ -586,9 +586,35 @@ export function SyncPage(props: {
                 <Button
                   size="small"
                   danger
-                  onClick={async () => {
-                    await deleteSyncChannel(session, r.id);
-                    await refresh();
+                  onClick={() => {
+                    Modal.confirm({
+                      title: `删除通道「${r.name || r.id}」？`,
+                      content: r.is_system_default
+                        ? "这是公司默认同步通道。删除后将自动重建并重挂库绑定，账号落点不会丢失。"
+                        : "删除后，仍挂在此通道上的绑定会自动改挂公司默认同步通道。",
+                      okText: "确认删除",
+                      okType: "danger",
+                      cancelText: "取消",
+                      onOk: async () => {
+                        setBusy(true);
+                        try {
+                          const res = await deleteSyncChannel(session, r.id);
+                          if (res.heal_error) {
+                            message.warning(`通道已删，自愈未完成：${res.heal_error}`);
+                          } else if (res.recreated_default) {
+                            message.success("已删除；公司默认同步通道已自动重建并重挂绑定");
+                          } else {
+                            message.success("已删除");
+                          }
+                          await refresh();
+                        } catch (e: any) {
+                          message.error(e.message || String(e));
+                          throw e;
+                        } finally {
+                          setBusy(false);
+                        }
+                      },
+                    });
                   }}
                 >
                   删除