Fix #493: Add multimodal meaning kernel extraction pipeline

- Added extract_meaning_kernels.py for processing PDF diagrams
- Extracts text using OCR (Tesseract) when available
- Analyzes diagram structure (type, dimensions, orientation)
- Generates structured meaning kernels with metadata
- Outputs JSON (machine-readable) and Markdown (human-readable)
- Includes test pipeline and documentation
- Supports single files and batch processing

Pipeline components:
- DiagramProcessor: Main processing engine
- MeaningKernel: Structured kernel representation
- PDF to image conversion
- OCR text extraction
- Structure analysis
- Kernel generation with confidence scoring

Acceptance criteria met:
✓ Processes academic PDF diagrams
✓ Extracts structured text meaning kernels
✓ Generates machine-readable JSON output
✓ Includes human-readable reports
✓ Supports batch processing
✓ Provides confidence scoring

scripts/multimodal/requirements.txt

@@ -0,0 +1,25 @@
+# Multimodal Meaning Kernel Extraction Pipeline
+# Required Python dependencies
+
+# Image processing
+Pillow>=10.0.0
+
+# OCR (Optical Character Recognition)
+pytesseract>=0.3.10
+
+# PDF processing
+pdf2image>=1.16.3
+
+# Optional: Enhanced computer vision
+# opencv-python>=4.8.0
+# numpy>=1.24.0
+
+# Optional: Machine learning for diagram classification
+# scikit-learn>=1.3.0
+# torch>=2.0.0
+# torchvision>=0.15.0
+
+# Development and testing
+# pytest>=7.4.0
+# black>=23.0.0
+# flake8>=6.0.0