feat: add Telegram confirmation UI components

Implements Phase 2 Task 7 - Telegram Confirmation UI:
- formatConfirmationMessage(): formats tool and args into readable message
- createConfirmationKeyboard(): creates approve/deny inline keyboard
- parseConfirmationCallback(): parses callback data from button clicks
- Full test coverage with vitest

All tests passing.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/frontends/telegram/index.ts

@@ -1,2 +1,8 @@
 export { createTelegramBot, type TelegramBotConfig } from './bot.js';
 export { isAllowedChat, createMessageHandler, createResetHandler } from './handlers.js';
+export {
+  formatConfirmationMessage,
+  createConfirmationKeyboard,
+  parseConfirmationCallback,
+  type ConfirmationCallbackData,
+} from './confirmations.js';