Add Telegram bot integration and related features

Implemented Telegram bot functionality, including settings management, subscriber tracking, and link generation for user interaction. Updated the backend to support new Telegram-related services and database entities. Enhanced the frontend to display Telegram options and allow users to open a chat with the bot. Localization strings were added for both English and Russian to support the new features. This integration aims to improve user engagement through Telegram notifications and interactions.

frontend/src/shared/lib/locales/en.ts

@@ -989,6 +989,42 @@ export const en = {
         Other: 'files outside the known directories — usually zero',
       },
     },
+    telegram: {
+      title: 'Telegram',
+      enable: 'Bot enabled',
+      enabled: 'Enabled',
+      disabled: 'Disabled',
+      saved: 'Saved, connection verified',
+      token: 'Bot token',
+      tokenKept: 'set — leave as is',
+      tokenHint: 'Issued by @BotFather. Never returned: only the fact that it is set.',
+      transport: 'Delivery',
+      transports: { Polling: 'Polling (getUpdates)', Webhook: 'Webhook' },
+      transportHint: {
+        Polling: 'The server pulls updates itself. Works without a public address and via a proxy.',
+        Webhook:
+          'Telegram calls your HTTPS endpoint. Needs a public domain; a proxy will not help.',
+      },
+      webhookUrl: 'Webhook URL',
+      webhookHint: 'Full https URL down to /api/telegram/webhook. The secret is generated for you.',
+      proxy: 'Proxy',
+      proxies: { None: 'No proxy' },
+      proxyHint: 'How to reach api.telegram.org.',
+      proxyHost: 'Host',
+      proxyPort: 'Port',
+      proxyUser: 'User',
+      proxyPassword: 'Password',
+      lastContact: 'Last contact',
+      subscribers: 'Subscribers',
+      noSubscribers: 'Nobody subscribed yet.',
+      user: 'User',
+      chat: 'Chat',
+      channels: 'Channels',
+      lastSeen: 'Last seen',
+      stopped: 'stopped',
+      openChat: 'Open bot chat',
+      linkFailed: 'Bot is not configured',
+    },
     maintenance: {
       title: 'Maintenance',
       warning: 'These actions are irreversible — data and files are deleted permanently.',