feat: add IsLark field to FeishuConfig to switch between Feishu and Lark domains (#1753)

* feat(feishu): add Lark (international) support via IsLark config field

Add IsLark field to FeishuConfig to switch between Feishu and Lark
domains. Also fix domain inconsistency where WS client defaulted to
LarkBaseUrl while HTTP client used FeishuBaseUrl.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: update documentation and web UI for Lark support

Add is_lark field to config example, feishu docs, i18n translations,
and web frontend form.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

pkg/channels/feishu/feishu_64.go

@@ -54,11 +54,15 @@ func NewFeishuChannel(cfg config.FeishuConfig, bus *bus.MessageBus) (*FeishuChan
 	)
 
 	tc := newTokenCache()
+	opts := []lark.ClientOptionFunc{lark.WithTokenCache(tc)}
+	if cfg.IsLark {
+		opts = append(opts, lark.WithOpenBaseUrl(lark.LarkBaseUrl))
+	}
 	ch := &FeishuChannel{
 		BaseChannel: base,
 		config:      cfg,
 		tokenCache:  tc,
-		client:      lark.NewClient(cfg.AppID, cfg.AppSecret, lark.WithTokenCache(tc)),
+		client:      lark.NewClient(cfg.AppID, cfg.AppSecret, opts...),
 	}
 	ch.SetOwner(ch)
 	return ch, nil
@@ -83,10 +87,15 @@ func (c *FeishuChannel) Start(ctx context.Context) error {
 
 	c.mu.Lock()
 	c.cancel = cancel
+	domain := lark.FeishuBaseUrl
+	if c.config.IsLark {
+		domain = lark.LarkBaseUrl
+	}
 	c.wsClient = larkws.NewClient(
 		c.config.AppID,
 		c.config.AppSecret,
 		larkws.WithEventHandler(dispatcher),
+		larkws.WithDomain(domain),
 	)
 	wsClient := c.wsClient
 	c.mu.Unlock()