feat: add deprecation tracking system

[Chemaclass]

TL;DR

Introduces deprecation tracking infrastructure with #[Deprecated] attribute, DeprecationScanner for analyzing codebase, and list:deprecated command to help manage technical debt and provide clear migration paths.

Summary

• #[Deprecated] attribute for marking deprecated classes, methods, and properties
• Support for deprecation reasons and alternative suggestions
• DeprecationScanner for automated codebase analysis
• list:deprecated command to scan and report all deprecated code with locations
• File location reporting for easy navigation to issues
• Comprehensive test coverage

Key Features

Mark Deprecated Code:

use Gacela\Framework\Attribute\Deprecated;

#[Deprecated(reason: 'Use NewService instead', alternative: 'App\NewService')]
class OldService
{
    #[Deprecated(reason: 'Use processV2() instead')]
    public function process(): void
    {
        // old implementation
    }
}

Scan for Deprecated Usage:

vendor/bin/gacela list:deprecated

Output:

• Lists all deprecated classes, methods, and properties
• Shows deprecation reasons and alternatives
• Reports file locations for each deprecated item
• Helps teams plan migration strategies

Use Cases

• Managing technical debt and planning refactoring
• Providing clear migration paths for deprecated APIs
• Automated scanning before major version releases
• Documenting why code is deprecated and what to use instead
• IDE integration for deprecation warnings