feat: add Telegram customers management system with admin panel

Implement comprehensive Telegram customers storage and management functionality:

Backend:
- Add database migration for telecart_customers table with indexes
- Create TelegramCustomer model with CRUD operations
- Implement TelegramCustomerService for business logic
- Add TelegramCustomerHandler for API endpoint (saveOrUpdate)
- Add TelegramCustomersHandler for admin API (getCustomers with pagination, filtering, sorting)
- Add SendMessageHandler for sending messages to customers via Telegram
- Create custom exceptions: TelegramCustomerNotFoundException, TelegramCustomerWriteNotAllowedException
- Refactor TelegramInitDataDecoder to separate decoding logic
- Add TelegramHeader enum for header constants
- Update SignatureValidator to use TelegramInitDataDecoder
- Register new routes in bastion/routes.php and src/routes.php

Frontend (Admin):
- Add CustomersView.vue component with PrimeVue DataTable
- Implement advanced filtering (text, date, boolean filters)
- Add column visibility toggle functionality
- Add global search with debounce
- Implement message sending dialog with validation
- Add Russian locale for PrimeVue components
- Add navigation link in App.vue
- Register route in router

Frontend (SPA):
- Add saveTelegramCustomer utility function
- Integrate automatic customer data saving on app initialization
- Extract user data from Telegram.WebApp.initDataUnsafe

The system automatically saves/updates customer data when users access the Telegram Mini App,
and provides admin interface for viewing, filtering, and messaging customers.

BREAKING CHANGE: None

frontend/spa/src/main.js

@@ -8,6 +8,7 @@ import {useSettingsStore} from "@/stores/SettingsStore.js";
 import ApplicationError from "@/ApplicationError.vue";
 import AppMetaInitializer from "@/utils/AppMetaInitializer.ts";
 import {injectYaMetrika} from "@/utils/yaMetrika.js";
+import {saveTelegramCustomer} from "@/utils/ftch.js";
 
 import {register} from 'swiper/element/bundle';
 import 'swiper/element/bundle';
@@ -44,6 +45,20 @@ settings.load()
             throw new Error('App disabled (maintenance mode)');
         }
     })
+    .then(async () => {
+        // Сохраняем данные Telegram-пользователя в базу данных
+        const userData = window.Telegram?.WebApp?.initDataUnsafe?.user;
+        if (userData) {
+            try {
+                console.debug('[Init] Saving Telegram customer data');
+                await saveTelegramCustomer(userData);
+                console.debug('[Init] Telegram customer data saved successfully');
+            } catch (error) {
+                // Не прерываем загрузку приложения, если не удалось сохранить пользователя
+                console.warn('[Init] Failed to save Telegram customer data:', error);
+            }
+        }
+    })
     .then(() => blocks.processBlocks(settings.mainpage_blocks))
     .then(async () => {
         console.debug('Load default filters for the main page');