Refactor configuration and enhance Telegram initData validation

- Improved formatting and readability in config.py and other files by adding line breaks.
- Introduced INIT_DATA_MAX_AGE_SECONDS to enforce replay protection for Telegram initData.
- Updated validate_init_data function to include max_age_seconds parameter for validation.
- Enhanced API to reject old initData based on the new max_age_seconds setting.
- Added tests for auth_date expiry and validation of initData in test_telegram_auth.py.
- Updated README with details on the new INIT_DATA_MAX_AGE_SECONDS configuration.

conftest.py

@@ -1,4 +1,5 @@
 """Pytest configuration. Set BOT_TOKEN so config module can be imported."""
+
 import os
 
 # Set before any project code imports config (which requires BOT_TOKEN).