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-integration.md

@@ -0,0 +1,174 @@
+# Exchange Integration
+
+## Status
+✅ Operational
+
+## Overview
+Integration service for connecting the exchange with external systems, blockchains, and data providers.
+
+## Architecture
+
+### Core Components
+- **Blockchain Connector**: Connects to blockchain RPC endpoints
+- **Data Feed Manager**: Manages external data feeds
+- **Webhook Handler**: Processes webhook notifications
+- **API Client**: Client for external exchange APIs
+- **Event Processor**: Processes integration events
+
+## Quick Start (End Users)
+
+### Prerequisites
+- Python 3.13+
+- Access to blockchain RPC endpoints
+- API keys for external exchanges
+
+### Installation
+```bash
+cd /opt/aitbc/apps/exchange-integration
+.venv/bin/pip install -r requirements.txt
+```
+
+### Configuration
+Set environment variables in `.env`:
+```bash
+BLOCKCHAIN_RPC_URL=http://localhost:8006
+EXTERNAL_EXCHANGE_API_KEY=your-api-key
+WEBHOOK_SECRET=your-webhook-secret
+```
+
+### Running the Service
+```bash
+.venv/bin/python main.py
+```
+
+## 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. Configure environment variables
+5. Run tests: `pytest tests/`
+
+### Project Structure
+```
+exchange-integration/
+├── src/
+│   ├── blockchain_connector/ # Blockchain integration
+│   ├── data_feed_manager/     # Data feed management
+│   ├── webhook_handler/        # Webhook processing
+│   ├── api_client/             # External API client
+│   └── event_processor/       # Event processing
+├── tests/                     # Test suite
+└── pyproject.toml             # Project configuration
+```
+
+### Testing
+```bash
+# Run all tests
+pytest tests/
+
+# Run blockchain integration tests
+pytest tests/test_blockchain.py
+
+# Run webhook tests
+pytest tests/test_webhook.py
+```
+
+## API Reference
+
+### Blockchain Integration
+
+#### Get Blockchain Status
+```http
+GET /api/v1/integration/blockchain/status
+```
+
+#### Sync Blockchain Data
+```http
+POST /api/v1/integration/blockchain/sync
+Content-Type: application/json
+
+{
+  "chain_id": "ait-mainnet",
+  "from_height": 1000,
+  "to_height": 2000
+}
+```
+
+### Data Feeds
+
+#### Subscribe to Data Feed
+```http
+POST /api/v1/integration/feeds/subscribe
+Content-Type: application/json
+
+{
+  "feed_type": "price|volume|orders",
+  "symbols": ["BTC_AIT", "ETH_AIT"]
+}
+```
+
+#### Get Feed Data
+```http
+GET /api/v1/integration/feeds/{feed_id}/data
+```
+
+### Webhooks
+
+#### Register Webhook
+```http
+POST /api/v1/integration/webhooks
+Content-Type: application/json
+
+{
+  "url": "https://example.com/webhook",
+  "events": ["order_filled", "price_update"],
+  "secret": "your-secret"
+}
+```
+
+#### Process Webhook
+```http
+POST /api/v1/integration/webhooks/process
+Content-Type: application/json
+X-Webhook-Secret: your-secret
+
+{
+  "event": "order_filled",
+  "data": {}
+}
+```
+
+## Configuration
+
+### Environment Variables
+- `BLOCKCHAIN_RPC_URL`: Blockchain RPC endpoint
+- `EXTERNAL_EXCHANGE_API_KEY`: API key for external exchanges
+- `WEBHOOK_SECRET`: Secret for webhook validation
+- `SYNC_INTERVAL`: Interval for blockchain sync (default: 60s)
+- `MAX_RETRIES`: Maximum retry attempts for failed requests
+- `TIMEOUT`: Request timeout in seconds
+
+### Integration Settings
+- **Supported Chains**: List of supported blockchain networks
+- **Data Feed Providers**: External data feed providers
+- **Webhook Endpoints**: Configurable webhook endpoints
+
+## Troubleshooting
+
+**Blockchain sync failed**: Check RPC endpoint connectivity and authentication.
+
+**Data feed not updating**: Verify API key and data feed configuration.
+
+**Webhook not triggered**: Check webhook URL and secret configuration.
+
+**API rate limiting**: Implement retry logic with exponential backoff.
+
+## Security Notes
+
+- Validate webhook signatures
+- Use HTTPS for all external connections
+- Rotate API keys regularly
+- Implement rate limiting for external API calls
+- Monitor for suspicious activity