Add comprehensive service breakdown: Nebius AI vs Modal.com usage

✅ Clear Service Division:
- Nebius AI: 'The Brain' - Language intelligence, AI reasoning, content analysis
- Modal.com: 'The Engine' - Heavy computation, OCR, vector operations, batch processing

✅ Specific Use Cases:
- Document analysis, query enhancement, research synthesis → Nebius AI
- OCR processing, FAISS indexing, distributed computing → Modal.com

✅ Integration Workflows:
- Step-by-step document processing pipeline showing which service handles each step
- Search workflow demonstrating coordinated service usage

✅ Feature Comparison Table:
- Clear checkmarks showing exactly which service handles which operations
- Notes on overlapping areas (embeddings: real-time vs batch)

✅ Specific API Endpoints:
- Listed exact endpoints that use each service
- Removed confusion about service responsibilities

This section provides crystal clear understanding of why both services are needed
and how they complement each other in the architecture.

README.md

@@ -343,18 +343,79 @@ npm run build
    - High-performance semantic similarity search
    - Persistent storage across sessions
 
-### **Service Integration**
-
-#### **Nebius AI** - Language Intelligence
-- **Purpose**: Advanced language understanding and content analysis
-- **Models**: DeepSeek-R1-0528 (chat), BAAI/bge-en-icl (embeddings)
-- **Functions**: Query enhancement, document analysis, research synthesis
-
-#### **Modal.com** - Heavy Computation
-- **Purpose**: Distributed processing for computationally intensive tasks
-- **Workloads**: OCR processing, FAISS indexing, batch document processing
-- **Resources**: Auto-scaling compute with persistent storage
-- **Live Deployment**: [Modal App](https://fazeelusmani18--knowledgebridge-main-fastapi-app.modal.run)
+### **Service Integration & Division of Responsibilities**
+
+## **🧠 Nebius AI: Language Intelligence & AI Reasoning**
+
+### **Used For:**
+- **📝 Document Analysis**: Classification, summarization, key points extraction, quality scoring
+- **🔍 Search Intelligence**: Query enhancement, intent understanding, relevance scoring  
+- **💭 AI Reasoning**: Research synthesis, explanations, conversational responses
+- **🎯 Embeddings**: Real-time text-to-vector conversion using BAAI/bge-en-icl model
+- **📊 Content Understanding**: All language comprehension and semantic analysis
+
+### **Specific Endpoints:**
+- `/api/analyze-document` - Document analysis with DeepSeek-R1 model
+- `/api/enhance-query` - AI-powered query improvement
+- `/api/embeddings` - Generate vector embeddings
+- `/api/research-synthesis` - Combine insights from multiple sources
+- `/api/ai-search` - Enhanced semantic search
+
+---
+
+## **⚡ Modal.com: Heavy Computation & Distributed Processing**
+
+### **Used For:**
+- **📄 OCR Processing**: PDF and image text extraction using Tesseract
+- **🔧 Vector Operations**: FAISS index building and high-performance search
+- **📦 Batch Processing**: Concurrent processing of large document collections
+- **💾 Infrastructure**: Serverless scaling, persistent storage, distributed compute
+- **🚀 Heavy Workloads**: All computationally intensive operations
+
+### **Specific Endpoints:**
+- `/api/documents/process/:id` - OCR text extraction via Modal
+- `/api/documents/index/build` - FAISS vector index creation  
+- `/api/documents/search/vector` - High-performance vector search
+- `/api/documents/process/batch` - Distributed batch processing
+
+### **Live Deployment**: [Modal App](https://fazeelusmani18--knowledgebridge-main-fastapi-app.modal.run)
+
+---
+
+## **🔄 How They Work Together**
+
+### **Document Processing Pipeline:**
+1. **Upload** → Local file storage
+2. **OCR** → **Modal** extracts text from PDFs/images
+3. **Analysis** → **Nebius** analyzes content and generates embeddings
+4. **Indexing** → **Modal** builds FAISS vector index
+5. **Search** → **Modal** performs vector search, **Nebius** scores relevance
+
+### **Search Workflow:**
+1. **Query Enhancement** → **Nebius** improves user queries
+2. **Vector Search** → **Modal** finds similar documents
+3. **Traditional Search** → Local database + external APIs
+4. **Ranking** → **Nebius** scores and ranks combined results
+5. **Synthesis** → **Nebius** generates insights
+
+---
+
+## **📊 Clear Division:**
+
+| Feature | Nebius AI | Modal.com |
+|---------|-----------|-----------|
+| **OCR Processing** | ❌ | ✅ |
+| **Document Analysis** | ✅ | ❌ |
+| **Vector Search** | ❌ | ✅ |
+| **Query Enhancement** | ✅ | ❌ |
+| **Batch Processing** | ❌ | ✅ |
+| **Embeddings** | ✅ | ✅* |
+| **Research Synthesis** | ✅ | ❌ |
+
+*Modal only for batch embeddings, Nebius for real-time
+
+**Nebius = "The Brain"** (AI intelligence)  
+**Modal = "The Engine"** (computational power)
 
 ### **Intelligent Fallbacks**
 - **Modal Unavailable**: Local processing for text files, basic search