feat: add LibreOffice support in Dockerfile and simplify extractor.py for legacy doc/ppt conversion

fix: upgrade torch to 2.5.1+cpu — fixes torch.distributed.tensor.device_mesh import error with latest transformers

fix: upgrade torch to 2.4.0+cpu (required by sentence-transformers>=3) and pin numpy<2 for binary compat

perf: use torch CPU-only wheel (~200MB vs 1.5GB) to speed up HF Spaces rebuild

upload ke HF