Update README.md

Fix generation_config: set decoder_start_token_id/forced_bos_token_id to mn_MN

Fix: base tokenizer, set bos/eos/pad, decoder_start_token_id=bos, forced_bos_token_id=mn_MN

Merge LoRA; set mn_MN decoder_start_token_id/forced_bos_token_id; add generation_config

initial commit