feat: add i18n descriptions to all hands and channels (#22)

Add [i18n.zh], [i18n.zh-TW], [i18n.ja], [i18n.ko], [i18n.de], [i18n.es]
sections with translated descriptions to:
- 15 Hand TOML files (hands/*/HAND.toml)
- 44 Channel TOML files (channels/*.toml)

This enables the website to display localized Hand and Channel descriptions
based on the user's selected language.

channels/webex.toml

@@ -5,6 +5,24 @@ category = "enterprise"
 icon = "🌐"
 protocol = "webhook"
 
+[i18n.zh]
+description = "Cisco Webex 适配器，在 Webex 空间中收发消息和通知"
+
+[i18n.zh-TW]
+description = "Cisco Webex 適配器，在 Webex 空間中收發訊息和通知"
+
+[i18n.ja]
+description = "Cisco Webexアダプター、Webexスペースでのメッセージングと通知"
+
+[i18n.ko]
+description = "Cisco Webex 어댑터, Webex 공간에서 메시지 및 알림 송수신"
+
+[i18n.de]
+description = "Cisco Webex-Adapter für Nachrichten und Benachrichtigungen in Webex-Spaces"
+
+[i18n.es]
+description = "Adaptador de Cisco Webex para mensajería y notificaciones en espacios de Webex"
+
 [metadata]
 url = "https://www.webex.com"
 docs = "https://developer.webex.com/docs/api/getting-started"