Refactor wallet transaction handling and introduce tonapi module

- Removed wallet transaction and transfer logic from the wallet domain.
- Introduced a new tonapi module to handle transactions and balance checks.
- Updated tests to reflect the new structure and ensure functionality remains intact.
- Added functionality for sending TON and USDT transfers through the tonapi module.
- Improved error handling and validation for payment balances.
- Cleaned up and organized imports across the codebase.

tests/002_test_client.py

@@ -1,4 +1,4 @@
-"""Unit tests for FragmentClient — initialization, validation, and cookie parsing."""
+"""Validate FragmentClient setup, cookie parsing, and wallet version checks."""
 
 import json