Add Conditional Middleware Support

[rakibdevs]

Added Conditional Middleware, a new PSR-15 compliant middleware that enables conditional execution of middleware based on request properties.

Use Cases

1. Path-based Middleware Application

// Authentication only for admin routes
$app->add(
    ConditionalMiddleware::forPath($authMiddleware, '/admin')
);

2. Method-based Middleware Application

// CSRF protection only for state-changing methods
$app->add(
    ConditionalMiddleware::forMethods($csrfMiddleware, ['POST', 'PUT', 'PATCH', 'DELETE'])
);

3. Combined Conditions

// Rate limiting only for API POST/PUT requests
$app->add(
    ConditionalMiddleware::forPathAndMethods(
        $rateLimitMiddleware,
        '/api',
        ['POST', 'PUT']
    )
);

4. Attribute-based Conditions

// Audit logging only for authenticated users
$app->add(
    new ConditionalMiddleware(
        $auditMiddleware,
        fn($request) => $request->getAttribute('user') !== null
    )
);

5. Complex Business Logic

// Apply middleware based on multiple criteria
$app->add(
    new ConditionalMiddleware(
        $specialMiddleware,
        fn($request) => 
            $request->getAttribute('subscription') === 'premium' &&
            !str_starts_with($request->getUri()->getPath(), '/public')
    )
);