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/nextcloud.toml

@@ -5,6 +5,24 @@ category = "iot"
 icon = "☁️"
 protocol = "rest-api"
 
+[i18n.zh]
+description = "Nextcloud Talk 适配器，在自托管 Nextcloud 实例中收发消息"
+
+[i18n.zh-TW]
+description = "Nextcloud Talk 適配器，在自架 Nextcloud 實例中收發訊息"
+
+[i18n.ja]
+description = "Nextcloud Talkアダプター、セルフホストNextcloudインスタンスでのメッセージング"
+
+[i18n.ko]
+description = "Nextcloud Talk 어댑터, 자체 호스팅 Nextcloud 인스턴스에서 메시지 송수신"
+
+[i18n.de]
+description = "Nextcloud Talk-Adapter für Nachrichten in selbstgehosteten Nextcloud-Instanzen"
+
+[i18n.es]
+description = "Adaptador de Nextcloud Talk para mensajería en instancias de Nextcloud autoalojadas"
+
 [metadata]
 url = "https://nextcloud.com"
 docs = "https://nextcloud-talk.readthedocs.io/en/latest/"