feat: enable chart recognition with PaddlePaddle 3.2.1

- Fixed WSL CUDA library path in ~/.bashrc
- Upgraded PaddlePaddle from 3.0.0 to 3.2.1
- Verified fused_rms_norm_ext API is now available
- Enabled chart recognition in ocr_service.py
- Updated CHART_RECOGNITION.md to reflect enabled status

Chart recognition now supports:
✅ Chart type identification
✅ Data extraction from charts
✅ Axis and legend parsing
✅ Converting charts to structured data

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

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

backend/app/services/ocr_service.py

@@ -214,7 +214,7 @@ class OCRService:
                     use_textline_orientation=False,
                     use_table_recognition=True,
                     use_formula_recognition=True,
-                    use_chart_recognition=False,  # Disable chart recognition (requires fused_rms_norm_ext not in PaddlePaddle 3.0.0)
+                    use_chart_recognition=True,  # Enable chart recognition (requires PaddlePaddle >= 3.2.0 for fused_rms_norm_ext)
                     layout_threshold=0.5,
                 )
                 logger.info(f"PP-StructureV3 engine ready (PaddlePaddle {paddle.__version__}, {'GPU' if self.use_gpu else 'CPU'} mode)")
@@ -232,7 +232,7 @@ class OCRService:
                         use_textline_orientation=False,
                         use_table_recognition=True,
                         use_formula_recognition=True,
-                        use_chart_recognition=False,  # Disable chart recognition
+                        use_chart_recognition=True,  # Enable chart recognition (CPU fallback mode)
                         layout_threshold=0.5,
                     )
                     logger.info("PP-StructureV3 engine ready (CPU mode - fallback)")