[Multi-Step Update] API Changes and Validation

[ervcz]

Description

Implement validation logic and API enhancements for prerequisite management.

Tasks

• Implement circular dependency detection
• Add prerequisite chain validation function
• Prevent channel assignment to packages with broken chains
• Add API endpoint for prerequisite chain visualization
• Implement admin tools for chain repair

func ValidatePrerequisiteChain(packageID string) error {
    ....
}