Move blockchain app READMEs to centralized documentation

- Relocate blockchain-event-bridge README content to docs/apps/blockchain/blockchain-event-bridge.md
- Relocate blockchain-explorer README content to docs/apps/blockchain/blockchain-explorer.md
- Replace app READMEs with redirect notices pointing to new documentation location
- Consolidate documentation in central docs/ directory for better organization

docs/apps/exchange/exchange.md

@@ -0,0 +1,221 @@
+# Exchange
+
+## Status
+✅ Operational
+
+## Overview
+Cross-chain exchange and trading platform supporting multiple blockchain networks with real-time price tracking and order matching.
+
+## Architecture
+
+### Core Components
+- **Order Book**: Central order book for all trading pairs
+- **Matching Engine**: Real-time order matching and execution
+- **Price Ticker**: Real-time price updates and market data
+- **Cross-Chain Bridge**: Bridge for cross-chain asset transfers
+- **Health Monitor**: System health monitoring and alerting
+- **API Server**: RESTful API for exchange operations
+
+### Supported Features
+- Multiple trading pairs
+- Cross-chain asset transfers
+- Real-time price updates
+- Order management (limit, market, stop orders)
+- Health monitoring
+- Multi-chain support
+
+## Quick Start (End Users)
+
+### Prerequisites
+- Python 3.13+
+- PostgreSQL database
+- Redis for caching
+- Access to blockchain RPC endpoints
+
+### Installation
+```bash
+cd /opt/aitbc/apps/exchange
+.venv/bin/pip install -r requirements.txt
+```
+
+### Configuration
+Set environment variables in `.env`:
+```bash
+DATABASE_URL=postgresql://user:pass@localhost/exchange
+REDIS_URL=redis://localhost:6379
+BLOCKCHAIN_RPC_URL=http://localhost:8006
+CROSS_CHAIN_ENABLED=true
+```
+
+### Running the Service
+```bash
+# Start the exchange server
+python server.py
+
+# Or use the production launcher
+bash deploy_real_exchange.sh
+```
+
+### Web Interface
+Open `index.html` in a browser to access the web interface.
+
+## Developer Guide
+
+### Development Setup
+1. Clone the repository
+2. Create virtual environment: `python -m venv .venv`
+3. Install dependencies: `pip install -r requirements.txt`
+4. Set up database: See database.py
+5. Configure environment variables
+6. Run tests: `pytest tests/`
+
+### Project Structure
+```
+exchange/
+├── server.py                # Main server
+├── exchange_api.py           # Exchange API endpoints
+├── multichain_exchange_api.py # Multi-chain API
+├── simple_exchange_api.py   # Simple exchange API
+├── cross_chain_exchange.py  # Cross-chain exchange logic
+├── real_exchange_integration.py # Real exchange integration
+├── models.py                 # Database models
+├── database.py               # Database connection
+├── health_monitor.py         # Health monitoring
+├── index.html                # Web interface
+├── styles.css                # Web styles
+├── update_price_ticker.js    # Price ticker update script
+└── scripts/                  # Utility scripts
+```
+
+### Testing
+```bash
+# Run all tests
+pytest tests/
+
+# Run API tests
+pytest tests/test_api.py
+
+# Run cross-chain tests
+pytest tests/test_cross_chain.py
+```
+
+## API Reference
+
+### Market Data
+
+#### Get Order Book
+```http
+GET /api/v1/orderbook?pair=BTC_AIT
+```
+
+#### Get Price Ticker
+```http
+GET /api/v1/ticker?pair=BTC_AIT
+```
+
+#### Get Market Summary
+```http
+GET /api/v1/market/summary
+```
+
+### Orders
+
+#### Place Order
+```http
+POST /api/v1/orders
+Content-Type: application/json
+
+{
+  "pair": "BTC_AIT",
+  "side": "buy|sell",
+  "type": "limit|market|stop",
+  "amount": 100,
+  "price": 1.0,
+  "user_id": "string"
+}
+```
+
+#### Get Order Status
+```http
+GET /api/v1/orders/{order_id}
+```
+
+#### Cancel Order
+```http
+DELETE /api/v1/orders/{order_id}
+```
+
+#### Get User Orders
+```http
+GET /api/v1/orders?user_id=string&status=open
+```
+
+### Cross-Chain
+
+#### Initiate Cross-Chain Transfer
+```http
+POST /api/v1/crosschain/transfer
+Content-Type: application/json
+
+{
+  "from_chain": "ait-mainnet",
+  "to_chain": "btc-mainnet",
+  "asset": "BTC",
+  "amount": 100,
+  "recipient": "address"
+}
+```
+
+#### Get Transfer Status
+```http
+GET /api/v1/crosschain/transfers/{transfer_id}
+```
+
+### Health
+
+#### Get Health Status
+```http
+GET /health
+```
+
+#### Get System Metrics
+```http
+GET /metrics
+```
+
+## Configuration
+
+### Environment Variables
+- `DATABASE_URL`: PostgreSQL connection string
+- `REDIS_URL`: Redis connection string
+- `BLOCKCHAIN_RPC_URL`: Blockchain RPC endpoint
+- `CROSS_CHAIN_ENABLED`: Enable cross-chain transfers
+- `MAX_ORDER_SIZE`: Maximum order size
+- `MIN_ORDER_SIZE`: Minimum order size
+- `TRADING_FEE_PERCENTAGE`: Trading fee percentage
+- `ORDER_TIMEOUT`: Order timeout in seconds
+
+### Trading Parameters
+- **Order Types**: limit, market, stop orders
+- **Order Sides**: buy, sell
+- **Trading Pairs**: Configurable trading pairs
+- **Fee Structure**: Percentage-based trading fees
+
+## Troubleshooting
+
+**Order not matched**: Check order book depth and price settings.
+
+**Cross-chain transfer failed**: Verify blockchain connectivity and bridge status.
+
+**Price ticker not updating**: Check WebSocket connection and data feed.
+
+**Database connection errors**: Verify DATABASE_URL and database server status.
+
+## Security Notes
+
+- Use API keys for authentication
+- Implement rate limiting for API endpoints
+- Validate all order parameters
+- Encrypt sensitive data at rest
+- Monitor for suspicious trading patterns
+- Regularly audit order history