Restore config/tokenizer files removed in 571683b
Commit 571683b8e795aff8314088132f571624a3d2c6bd ("Add reference OpenVINO IRs") replaced the full checkpoint with only the OpenVINO IR files and metadata.json, dropping config.json, generation_config.json, and all tokenizer/preprocessor files. This breaks AutoConfig.from_pretrained(..., revision="ov") since there is no model_type in config.json (there is no config.json at all), which in turn breaks optimum-intel's optimum_pipeline(..., revision="ov") / OVModelForSpeechSeq2Seq.from_pretrained loading path (see optimum-intel tests/openvino/test_modeling.py::PipelineTest::test_seq2seq_load_from_hub).
This PR restores the files removed in that commit (as they were in f50ad03ad4b24324d29328285a2e019d081135aa, the last commit before the reference IR files were added), keeping the newer OpenVINO IR + metadata.json files.