0.1.9.2: feat(tokenizer): add attention mask support and reorder special tokens

This commit introduces support for returning attention masks during tokenization, which is essential for models that require masking padded tokens. Additionally, the special tokens have been reordered to ensure consistent IDs (pad_token_id=0, unknown_token_id=1, end_of_text_token_id=2). The changes improve the tokenizer's compatibility with transformer-based models.