feat: Add comprehensive health check endpoints with real-time monitoring

[virajbhartiya]

Health Check Implementation

This PR adds comprehensive health monitoring capabilities to the parity client with real-time data collection and service connectivity testing.

Features Added

HTTP Health Endpoints

• /health - Basic health check with service configuration status
• /health/detailed - Detailed health information with live service connectivity tests
• /health/ready - Kubernetes readiness probe with dependency validation
• /health/live - Kubernetes liveness probe for application status

CLI Health Command

• parity-client health - Command line health check
• parity-client health --detailed - Detailed health information
• parity-client health --endpoint <url> - Custom endpoint support
• parity-client health --timeout <duration> - Configurable timeout

Real-Time Data Collection

• Uptime tracking since application start
• Version information from git tags and build metadata
• Live connectivity tests to blockchain, IPFS, and runner services
• Latency measurements for each service
• Real configuration values from environment

Technical Implementation

Service Health Checks

• Blockchain: Uses ethclient.Dial() and BlockNumber() for connectivity
• IPFS: Uses shell.Version() for IPFS API connectivity
• Runner: HTTP health check to runner service endpoint
• Error handling with detailed error messages

Version Management

• Version package for centralized version management
• Build-time injection of git tags, commit SHA, and build timestamp
• Runtime platform and Go version information

Kubernetes Integration

• Readiness probe returns 503 if dependencies unavailable
• Liveness probe for application status check
• Proper HTTP status codes for monitoring systems

Usage Examples

Command Line

# Basic health check
parity-client health

# Detailed health information
parity-client health --detailed

# Custom endpoint with timeout
parity-client health --endpoint http://localhost:8080 --timeout 30s

HTTP API

# Basic health check
curl http://localhost:3000/health

# Detailed health information
curl http://localhost:3000/health/detailed

# Kubernetes probes
curl http://localhost:3000/health/ready
curl http://localhost:3000/health/live

Response Format

Basic Health Check

{
  "status": "healthy",
  "timestamp": "2024-01-15T10:30:00Z",
  "version": "v1.0.0",
  "uptime": "2h30m15s",
  "services": {
    "blockchain": "configured",
    "ipfs": "configured",
    "runner": "configured"
  }
}

Detailed Health Check

{
  "status": "healthy",
  "timestamp": "2024-01-15T10:30:00Z",
  "version": "v1.0.0",
  "uptime": "2h30m15s",
  "services": {
    "blockchain": {
      "status": "healthy",
      "last_check": "2024-01-15T10:29:55Z",
      "latency": "125ms"
    },
    "ipfs": {
      "status": "healthy",
      "last_check": "2024-01-15T10:29:58Z",
      "latency": "45ms"
    },
    "runner": {
      "status": "healthy",
      "last_check": "2024-01-15T10:30:00Z",
      "latency": "78ms"
    }
  },
  "config": {
    "server_host": "0.0.0.0",
    "server_port": 3000,
    "blockchain_rpc": "https://your-blockchain-node.com",
    "ipfs_endpoint": "http://localhost:5001",
    "runner_url": "http://localhost:8080"
  }
}