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/xmpp.toml

@@ -5,6 +5,24 @@ category = "messaging"
 icon = "📨"
 protocol = "xmpp"
 
+[i18n.zh]
+description = "XMPP 适配器，通过可扩展消息和出席协议收发消息"
+
+[i18n.zh-TW]
+description = "XMPP 適配器，透過可擴展訊息和出席協議收發訊息"
+
+[i18n.ja]
+description = "XMPPアダプター、XMPPプロトコルによるメッセージング"
+
+[i18n.ko]
+description = "XMPP 어댑터, XMPP 프로토콜을 통한 메시지 송수신"
+
+[i18n.de]
+description = "XMPP-Adapter für Nachrichten über das Extensible Messaging and Presence Protocol"
+
+[i18n.es]
+description = "Adaptador XMPP para mensajería a través del protocolo extensible de mensajería y presencia"
+
 [metadata]
 url = "https://xmpp.org"
 docs = "https://xmpp.org/extensions/"