Add supply chain tokenization system for educational content

[Naomi-Gift]

Resolves #59

• Implement content tokenization with mint, transfer, and ownership management
• Add provenance tracking for complete ownership history and chain verification
• Support multiple content types: Course, Material, Lesson, Assessment, Certificate
• Include rich metadata: title, description, content hash, license, tags
• Add comprehensive test suite for tokenization and provenance features
• Emit events for minting, transfers, provenance updates, and metadata changes

[Naomi-Gift]

@ISTIFANUS-N Pull request ready for review

[ISTIFANUS-N]

@Naomi-Gift resolve conflicts.

[Naomi-Gift]

@ISTIFANUS-N done