Add name translation fix for OPUS-MT - correct 'sand geese' to 'Zhang Shaian'

Revert to OPUS-MT translation by default - better name handling

Fix translation hallucinations by adding stop sequences and improving cleanup

Improve translation prompt to ensure completeness for titles and all sentences

Improve translation completeness: better paragraph splitting for headings, improved prompts, lower min length for titles

Fix: Enable PDF processing for content extraction and improve short translation handling

Fix Qwen2.5 translation truncation: increase max_length to 1024, dynamic max_new_tokens (300-800), less aggressive cleanup

Remove unused messages variable

Fix: Save bilingual file to current directory, prevent PDF/bilingual file duplication, ensure Message section only uses bilingual content

Integrate improved Qwen2.5 translation into document_processing_agent with fallback to OPUS-MT

Fix: Use actual bilingual file from document_sources instead of hardcoded test file

Initial commit for HF Space deployment