- api_server.py: rename 'filename' to 'file_name' in upload_file log extra
dict to avoid collision with Python logging's reserved LogRecord attribute
- test_e2e_ocr.py: replace return statements with assert in test functions
to fix PytestReturnNotNoneWarning
3-phase pipeline to solve LLM prompt overflow from too many OCR elements:
Phase 1 (generate_skeleton): compressed layout schema → skeleton JRXML
Phase 2 (refine_layout): sampled coordinates → pixel-level position tuning
Phase 3 (map_fields): OCR field names → replace $F{field_N} placeholders
Only triggered when layout_schema.total_rows > 0 on initial_generation intent.
Text requests and all other intents are unaffected (zero behavior change).