Add Telegram cancellation import functionality with tests and documentation

- Implemented Telegram cancellation parsing logic in `telegramCancellationParser.js`.
- Created unit tests for cancellation parsing in `telegramCancellationParser.test.js`.
- Developed integration tests for Telegram import service in `telegramImport.integration.test.js`.
- Added API tests for Telegram import endpoints in `telegramImportApi.test.js`.
- Introduced service tests for Telegram import logic in `telegramImportService.test.js`.
- Documented the Telegram cancellation import process in `telegram-cancellation-import.md`.
- Built a React component for managing Telegram imports in `TelegramImportPanel.jsx`.

backend/test/alertNotificationService.test.js

@@ -8,6 +8,17 @@ const {
 } = require('../src/services/alertNotificationService');
 const { createFirebaseMessaging, getFirebaseConfig } = require('../src/config/firebase');
 
+test('expires a cancellation at Minsk midnight and does not send a stale push', async () => {
+  const now = new Date('2026-10-02T20:59:00Z');
+  const alert = { id: 1, alert_type: 'cancellation', end_time: '2026-10-02T21:00:00Z' };
+  assert.equal(buildAlertCreatedMessage(alert, { now }).android.ttl, 60_000);
+  let sends = 0;
+  const service = new AlertNotificationService({ enabled: true, now: () => new Date('2026-10-02T21:00:00Z'),
+    getMessaging: async () => { sends++; }, logger: createLogger() });
+  assert.deepEqual(await service.sendAlertCreated(alert), { sent: false, skipped: true, reason: 'expired' });
+  assert.equal(sends, 0);
+});
+
 function createLogger() {
   const errors = [];
   return {
@@ -23,6 +34,7 @@ test('sends an exact data-only alert-created message with string-only data', asy
   const service = new AlertNotificationService({
     enabled: true,
     topic: 'route_alerts',
+    now: () => new Date('2026-07-11T08:30:00Z'),
     androidChannelId: 'route_alerts',
     messaging: {
       async send(message) {
@@ -64,7 +76,8 @@ test('sends an exact data-only alert-created message with string-only data', asy
       body: 'Задержка около 15 минут'
     },
     android: {
-      priority: 'high'
+      priority: 'high',
+      ttl: 3_600_000
     }
   });
   assert.equal('notification' in messages[0], false);