fix: 按 K-00 约定修复 Go SDK 断线重交与退避

sdk/go/api.go

@@ -73,6 +73,11 @@ func (c *Client) Directory(ctx context.Context, cursor, query string, limit int)
 
 // WatchPresence 订阅上下线；ids 为空且 all 为 true 表示全部。
 func (c *Client) WatchPresence(ctx context.Context, ids []string, all bool) error {
+	c.mu.Lock()
+	c.watchIDs = append([]string(nil), ids...)
+	c.watchAll = all
+	c.watchSet = true
+	c.mu.Unlock()
 	req := map[string]any{"v": 1, "type": "presence.watch", "rid": c.nextRID(), "all": all}
 	if len(ids) > 0 {
 		req["ids"] = ids
@@ -131,11 +136,11 @@ func (c *Client) ChangeLoginPassword(ctx context.Context, oldPassword, newPasswo
 		if c.transport != nil {
 			c.transport.SetCredential(d.SessionToken)
 		}
+		h := c.onSession
+		tok := d.SessionToken
 		c.mu.Unlock()
-		if c.onSession != nil {
-			c.cbMu.Lock()
-			c.onSession(d.SessionToken)
-			c.cbMu.Unlock()
+		if h != nil {
+			h(tok)
 		}
 	}
 	return nil