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/signal.toml

@@ -5,6 +5,24 @@ category = "messaging"
 icon = "🔒"
 protocol = "rest-api"
 
+[i18n.zh]
+description = "Signal 适配器，通过 Signal CLI 进行端到端加密安全通信"
+
+[i18n.zh-TW]
+description = "Signal 適配器，透過 Signal CLI 進行端對端加密安全通訊"
+
+[i18n.ja]
+description = "Signalアダプター、Signal CLIによるエンドツーエンド暗号化メッセージング"
+
+[i18n.ko]
+description = "Signal 어댑터, Signal CLI를 통한 종단간 암호화 보안 메시지 송수신"
+
+[i18n.de]
+description = "Signal-Adapter für sichere Ende-zu-Ende-verschlüsselte Nachrichten über Signal CLI"
+
+[i18n.es]
+description = "Adaptador de Signal para mensajería segura con cifrado de extremo a extremo a través de Signal CLI"
+
 [metadata]
 url = "https://signal.org"
 docs = "https://github.com/AsamK/signal-cli"