chore: add bare timeseries tag, remove ineffective modality field

chore: fix modality field, drop modality tag, sync language

chore: translate to English, sync source metadata, add format:tsfile tag

chore: translate README to English and add format:tsfile tag

chore: normalize tsfile dataset metadata

Restore dataset card and add timeseries modality tag

Upload README.md with huggingface_hub

Rewrite dataset card in English; add tsfile tag

Organize GiftEval TsFiles by original frequency

Copy GiftEval TsFiles into frequency directories

Refresh dataset card and viewer status

Replace with converted GiftEval subset ett2

initial commit