Fix transformers ImportError by pinning compatible versions

- Updated torch to >=2.0.0 (was unpinned)
- Updated transformers to >=4.35.0 (from >=4.30.0)
- Added protobuf>=3.20.0 (required by transformers)
- Added accelerate>=0.20.0 (improves model loading)

This resolves the ImportError for AutoTokenizer and AutoModelForSeq2SeqLM
that prevented the translation feature from working.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

requirements.txt

@@ -2,7 +2,9 @@ streamlit
 huggingface_hub
 lxml
 stanza
-torch
-transformers>=4.30.0
+torch>=2.0.0
+transformers>=4.35.0
 sentencepiece>=0.1.99
+protobuf>=3.20.0
+accelerate>=0.20.0
 pyswip>=0.2.10