feat(i18n): add zh_Hant and ja_JP translations to all adapter YAML files

- Add zh_Hant (Traditional Chinese) to all 17 adapter YAML metadata and config fields
- Add ja_JP translations to global adapters (Telegram, Discord, Slack, Lark, LINE)
- Fix buggy zh_Hant in line.yaml and slack.yaml (contained simplified Chinese)
- Add zh_Hant field to backend I18nString model
- Add adapter category grouping with locale-aware ordering
- Add webhook Cloud CTA for community edition users
- Fix wizard progress not clearing on skip/complete

src/langbot/pkg/platform/sources/kook.yaml

@@ -5,16 +5,21 @@ metadata:
   label:
     en_US: KOOK
     zh_Hans: KOOK
+    zh_Hant: KOOK
   description:
     en_US: KOOK Adapter (formerly KaiHeiLa)
     zh_Hans: KOOK 适配器(原开黑啦)，支持频道消息和私聊消息
+    zh_Hant: KOOK 適配器（原開黑啦），支援頻道訊息和私聊訊息
   icon: kook.png
 spec:
+  categories:
+    - china
   config:
     - name: token
       label:
         en_US: Bot Token
         zh_Hans: 机器人令牌
+        zh_Hant: 機器人令牌
       type: string
       required: true
       default: ""