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/explorer/simple-explorer.md

@@ -0,0 +1,207 @@
+# Simple Explorer
+
+## Status
+✅ Operational
+
+## Overview
+Simple blockchain explorer for viewing blocks, transactions, and addresses on the AITBC blockchain.
+
+## Architecture
+
+### Core Components
+- **Block Viewer**: Displays block information and details
+- **Transaction Viewer**: Displays transaction information
+- **Address Viewer**: Displays address details and transaction history
+- **Search Engine**: Searches for blocks, transactions, and addresses
+- **Data Fetcher**: Fetches data from blockchain RPC
+
+## Quick Start (End Users)
+
+### Prerequisites
+- Python 3.13+
+- Access to blockchain RPC endpoint
+- Web browser
+
+### Installation
+```bash
+cd /opt/aitbc/apps/simple-explorer
+.venv/bin/pip install -r requirements.txt
+```
+
+### Configuration
+Set environment variables in `.env`:
+```bash
+BLOCKCHAIN_RPC_URL=http://localhost:8006
+CHAIN_ID=ait-mainnet
+EXPLORER_PORT=8080
+```
+
+### Running the Service
+```bash
+.venv/bin/python main.py
+```
+
+### Access Explorer
+Open `http://localhost:8080` in a web browser to access the explorer.
+
+## 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 blockchain RPC endpoint
+5. Run tests: `pytest tests/`
+
+### Project Structure
+```
+simple-explorer/
+├── src/
+│   ├── block_viewer/       # Block viewing
+│   ├── transaction_viewer/ # Transaction viewing
+│   ├── address_viewer/     # Address viewing
+│   ├── search_engine/      # Search functionality
+│   └── data_fetcher/       # Data fetching
+├── templates/              # HTML templates
+├── static/                  # Static assets
+├── tests/                  # Test suite
+└── pyproject.toml          # Project configuration
+```
+
+### Testing
+```bash
+# Run all tests
+pytest tests/
+
+# Run data fetcher tests
+pytest tests/test_fetcher.py
+
+# Run search engine tests
+pytest tests/test_search.py
+```
+
+## API Reference
+
+### Block Viewing
+
+#### Get Block by Height
+```http
+GET /api/v1/explorer/block/{height}
+```
+
+#### Get Block by Hash
+```http
+GET /api/v1/explorer/block/hash/{hash}
+```
+
+#### Get Latest Blocks
+```http
+GET /api/v1/explorer/blocks/latest?limit=20
+```
+
+### Transaction Viewing
+
+#### Get Transaction by Hash
+```http
+GET /api/v1/explorer/transaction/{hash}
+```
+
+#### Get Transactions by Address
+```http
+GET /api/v1/explorer/transactions/address/{address}?limit=50
+```
+
+#### Get Latest Transactions
+```http
+GET /api/v1/explorer/transactions/latest?limit=50
+```
+
+### Address Viewing
+
+#### Get Address Details
+```http
+GET /api/v1/explorer/address/{address}
+```
+
+#### Get Address Balance
+```http
+GET /api/v1/explorer/address/{address}/balance
+```
+
+#### Get Address Transactions
+```http
+GET /api/v1/explorer/address/{address}/transactions?limit=50
+```
+
+### Search
+
+#### Search
+```http
+GET /api/v1/explorer/search?q={query}
+```
+
+#### Search Blocks
+```http
+GET /api/v1/explorer/search/blocks?q={query}
+```
+
+#### Search Transactions
+```http
+GET /api/v1/explorer/search/transactions?q={query}
+```
+
+#### Search Addresses
+```http
+GET /api/v1/explorer/search/addresses?q={query}
+```
+
+### Statistics
+
+#### Get Chain Statistics
+```http
+GET /api/v1/explorer/stats
+```
+
+#### Get Network Status
+```http
+GET /api/v1/explorer/network/status
+```
+
+## Configuration
+
+### Environment Variables
+- `BLOCKCHAIN_RPC_URL`: Blockchain RPC endpoint
+- `CHAIN_ID`: Blockchain chain ID
+- `EXPLORER_PORT`: Explorer web server port
+- `CACHE_ENABLED`: Enable data caching
+- `CACHE_TTL`: Cache time-to-live in seconds
+
+### Display Parameters
+- **Blocks Per Page**: Number of blocks per page (default: 20)
+- **Transactions Per Page**: Number of transactions per page (default: 50)
+- **Address History Limit**: Transaction history limit per address
+
+### Caching
+- **Block Cache**: Cache block data
+- **Transaction Cache**: Cache transaction data
+- **Address Cache**: Cache address data
+- **Cache TTL**: Time-to-live for cached data
+
+## Troubleshooting
+
+**Explorer not loading**: Check blockchain RPC connectivity and explorer port.
+
+**Data not updating**: Verify cache configuration and RPC endpoint availability.
+
+**Search not working**: Check search index and data availability.
+
+**Address history incomplete**: Verify blockchain sync status and data availability.
+
+## Security Notes
+
+- Use HTTPS in production
+- Implement rate limiting for API endpoints
+- Sanitize user inputs
+- Cache sensitive data appropriately
+- Monitor for abuse
+- Regularly update dependencies