feat(i18n): add English support for host-side chat messages

Wrap all user-facing chat text in src/channels with a host-side t()
translator (Chinese is the identity default, so untranslated text is
always sent verbatim in Chinese). English is selected via the host
plugin config `language: en` or the DSH_IM_LANGUAGE environment
variable, and the settings UI keeps following the DSH web locale.

- add src/channels/shared/i18n.mjs with setImHostLanguage/t() and a
  Chinese-key -> English dictionary split by area (shared + channels)
- complete the English dictionary for every t() key in src/channels,
  including the feishu channel (welcome/help, repair flow, interactive
  cards, watch flow) and the shared command/approval/stream text
- wrap previously untranslated chat-facing strings in feishu bridge,
  feishu runtime, editable-message-stream, harness-client,
  connection-test and image-prompt
- dedupe dictionary entries that existed in multiple channel files and
  canonicalize conflicting translations into the shared dictionaries
- extend the i18n unit test to decode string-literal escapes so keys
  containing \n are checked correctly
- document the language switch in README.md, README.en.md and
  CHANGELOG.md, and rebuild lib/index.js

Added English support for bot chat messages across all nine IM
channels and AI Office without changing any Chinese output.

src/channels/telegram/telegram-api.mjs

@@ -1,5 +1,6 @@
 import { fetchFileStream } from '../shared/file-download.mjs';
 import { fetchImageBuffer } from '../shared/image-prompt.mjs';
+import { t } from '../shared/i18n.mjs';
 
 const DEFAULT_BASE_URL = 'https://api.telegram.org/';
 const TELEGRAM_FILE_HOSTS = Object.freeze(['api.telegram.org']);
@@ -329,7 +330,7 @@ export async function inspectTelegramToken(token, options = {}) {
   if (!bot?.id || bot?.is_bot !== true) throw new Error('Telegram token does not belong to a bot');
   return {
     platformId: String(bot.id),
-    name: cleanString([bot.first_name, bot.last_name].filter(Boolean).join(' ')) ?? 'Telegram机器人',
+    name: cleanString([bot.first_name, bot.last_name].filter(Boolean).join(' ')) ?? t('Telegram机器人'),
     username: cleanString(bot.username),
   };
 }