Unify AI — Gradio + LangGraph RAG (Vector → Optional GraphRAG)

A lightweight AI assistant service with a Gradio UI, LangGraph workflow orchestration, and RAG retrieval (Chroma via LlamaIndex).
Local development can run with Ollama, while production uses OpenAI API.

✅ Current: Vector RAG (LlamaIndex → Chroma)
🔜 Optional: KG-augmented RAG / GraphRAG (Graph Retriever → Neo4j)

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Architecture

User (Browser)
      │
      ▼
┌───────────────────────────────┐
│            Gradio UI           │
│  - Question input              │
│  - Answer + Sources output     │
└───────────────┬───────────────┘
                │
                ▼
┌───────────────────────────────┐
│          LangGraph             │
│  Workflow Orchestration        │
│  - State management            │
│  - Retry / branching logic     │
└───────────────┬───────────────┘
                │
                ▼
┌─────────────────────────────────────────────────────┐
│                 Retrieval Layer                      │
│                                                     │
│  (Current) Vector RAG                               │
│   LlamaIndex Retriever ─────▶ Chroma (Vector DB)     │
│                                                     │
│  (Future, Optional) KG-augmented RAG                 │
│   Graph Retriever ─────────▶ Neo4j (Knowledge Graph) │
└───────────────┬─────────────────────────────────────┘
                │
                ▼
┌───────────────────────────────┐
│          LLM Layer             │
│  Prompting + Invocation        │
│                               │
│  - Local Dev: Ollama           │
│  - Production: OpenAI API      │
└───────────────┬───────────────┘
                │
                ▼
        Answer + Citations