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/confirmations.test.ts

@@ -0,0 +1,36 @@
+import { describe, it, expect } from 'vitest';
+import { formatConfirmationMessage, parseConfirmationCallback } from './confirmations.js';
+
+describe('formatConfirmationMessage', () => {
+  it('formats tool and args into readable message', () => {
+    const message = formatConfirmationMessage('shell.exec', { cmd: 'ls -la' });
+
+    expect(message).toContain('shell.exec');
+    expect(message).toContain('ls -la');
+  });
+});
+
+describe('parseConfirmationCallback', () => {
+  it('parses approve callback data', () => {
+    const result = parseConfirmationCallback('confirm:abc123:approve');
+
+    expect(result).toEqual({
+      id: 'abc123',
+      approved: true,
+    });
+  });
+
+  it('parses deny callback data', () => {
+    const result = parseConfirmationCallback('confirm:abc123:deny');
+
+    expect(result).toEqual({
+      id: 'abc123',
+      approved: false,
+    });
+  });
+
+  it('returns null for invalid callback data', () => {
+    expect(parseConfirmationCallback('invalid')).toBeNull();
+    expect(parseConfirmationCallback('other:data')).toBeNull();
+  });
+});

src/frontends/telegram/confirmations.ts

@@ -0,0 +1,43 @@
+import { InlineKeyboard } from 'grammy';
+
+export function formatConfirmationMessage(tool: string, args: Record<string, unknown>): string {
+  const argsStr = Object.entries(args)
+    .map(([key, value]) => `  ${key}: ${JSON.stringify(value)}`)
+    .join('\n');
+
+  return `🔐 **Confirmation Required**
+
+Tool: \`${tool}\`
+Arguments:
+${argsStr || '  (none)'}
+
+Approve this action?`;
+}
+
+export function createConfirmationKeyboard(confirmationId: string): InlineKeyboard {
+  return new InlineKeyboard()
+    .text('✅ Approve', `confirm:${confirmationId}:approve`)
+    .text('❌ Deny', `confirm:${confirmationId}:deny`);
+}
+
+export interface ConfirmationCallbackData {
+  id: string;
+  approved: boolean;
+}
+
+export function parseConfirmationCallback(data: string): ConfirmationCallbackData | null {
+  const parts = data.split(':');
+  if (parts.length !== 3 || parts[0] !== 'confirm') {
+    return null;
+  }
+
+  const [, id, action] = parts;
+  if (action !== 'approve' && action !== 'deny') {
+    return null;
+  }
+
+  return {
+    id,
+    approved: action === 'approve',
+  };
+}

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';