Implement ZKP Generate Proof DTO

[llinsss]

Description

Reimplement the ZKP generate proof DTO that was deleted. This defines the data structure for generating zero-knowledge proofs.

What was deleted

• backend/src/modules/zkp/dto/generate-proof.dto.ts: DTO for proof generation

Implementation details

• Define input data structure
• Add validation decorators
• Document field requirements
• Add TypeScript types
• Include example payloads

Acceptance criteria

• DTO is properly typed
• Validation rules are comprehensive
• Documentation is clear
• Follows NestJS patterns

Priority

High - Blockchain functionality

Labels

backend, blockchain, Nestjs