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

.cursorignore

@@ -22,8 +22,77 @@ dist-ssr
 *.sln
 *.sw?
 
-src/*
+# Cursor ignore patterns
+
 frontend/spa/node_modules
+frontend/admin/node_modules
 module/oc_telegram_shop/upload/oc_telegram_shop/vendor
 module/oc_telegram_shop/upload/image
 module/oc_telegram_shop/upload/oc_telegram_shop/.phpunit.cache
+
+# Dependencies
+node_modules/
+vendor/
+composer.lock
+package-lock.json
+yarn.lock
+
+# Build outputs
+dist/
+build/
+*.phar
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# Logs
+*.log
+logs/
+storage/logs/
+
+# Cache
+storage/cache/
+.cache/
+
+# Environment
+.env
+.env.local
+.env.*.local
+
+# Database
+*.sql
+*.sqlite
+*.db
+
+# Temporary files
+tmp/
+temp/
+*.tmp
+
+# OS
+.DS_Store
+Thumbs.db
+
+# OpenCart specific
+src/upload/system/
+src/upload/image/cache/
+src/storage/
+
+# Test fixtures (large files)
+tests/fixtures/*.sql
+tests/fixtures/*.json
+
+# Documentation builds
+docs/_build/
+
+# Coverage reports
+coverage/
+.nyc_output/
+
+# Docker
+docker-compose.override.yml
+