Add daemon functionality with chico start and chico stop commands using daemonize crate

[Copilot]

This PR implements daemon functionality for the Chico server, allowing users to start and stop the server as a background process without blocking their shell.

New Features

chico start Command

• Starts the Chico server as a background daemon process
• Validates configuration before starting
• Prevents multiple daemon instances using PID file management
• Cross-platform support with proper Unix daemonization using the daemonize crate

chico start --config path/to/config.chico

chico stop Command

• Gracefully terminates the background daemon
• Uses process signals for clean shutdown
• Removes PID file after successful termination

chico stop

Implementation Details

• Unix Daemonization: Uses the daemonize crate for proper Unix daemon functionality including process forking, terminal detachment, and signal handling
• Windows Compatibility: Maintains existing process spawning approach for Windows platforms
• PID File Management: Uses temporary directory to store daemon process ID
• Process Control: Platform-specific process management (Unix signals, Windows taskkill)
• Error Handling: Comprehensive error handling for edge cases:
  • Attempting to start when daemon already running
  • Attempting to stop when no daemon is running
  • Invalid configuration validation

Testing

Added comprehensive integration tests covering:

• Start/stop daemon lifecycle
• Duplicate start prevention
• Stop when not running scenarios
• Invalid configuration handling

All tests use serial execution to prevent conflicts and ensure reliable testing.

Documentation

Updated README.md with:

• New daemon command examples
• Available commands reference
• Usage instructions for background operation

Fixes #118.

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[Alirexaa]

@copilot , Use daemonize crate for Unix platform

[Copilot]

@copilot , Use daemonize crate for Unix platform

Implemented! I've integrated the daemonize crate for Unix platforms as requested. The changes include:

• Added daemonize = "0.5" dependency for Unix targets only
• Modified the Unix daemon implementation to use proper daemonization via the daemonize crate
• Maintained Windows compatibility with the existing approach
• The daemon now properly forks, detaches from terminal, and handles PID files using Unix daemon best practices

The implementation spawns a child process with --daemon-mode flag, which then uses the daemonize crate to properly daemonize itself. This provides better process isolation and follows Unix daemon conventions.

Commit: 73c7959