Enhance API and configuration for Telegram miniapp

- Added support for CORS origins and a new environment variable for miniapp access control.
- Implemented date validation for API requests to ensure correct date formats.
- Updated FastAPI app to allow access without Telegram initData for local development.
- Enhanced error handling and logging for better debugging.
- Added tests for API functionality and Telegram initData validation.
- Updated README with new environment variable details and testing instructions.
- Modified Docker and Git ignore files to include additional directories and files.

handlers/errors.py

@@ -10,4 +10,4 @@ logger = logging.getLogger(__name__)
 async def error_handler(update: object, context: ContextTypes.DEFAULT_TYPE) -> None:
     logger.exception("Exception while handling an update")
     if isinstance(update, Update) and update.effective_message:
-        await update.effective_message.reply_text("Something went wrong. Please try again later.")
+        await update.effective_message.reply_text("Произошла ошибка. Попробуйте позже.")