feat: add support for kyc

[Tranquil-Flow]

Note

Introduce RegisterKyc and DiscloseKyc proof types with full server routing, validation, and metadata handling.

• Backend
  • Types (src/types.rs):
    • Add ProofRequest::{RegisterKyc, DiscloseKyc} variants with fields mirroring existing register/disclose patterns.
    • Extend ProofType with RegisterKyc and DiscloseKyc, including Display, Into<i32>, and TryFrom<i32> mappings.
    • Update ProofRequest::circuit() to cover new variants.
  • Server (src/server.rs):
    • Include KYC variants in feature-gated request validation for submit_request.
    • Handle endpoint metadata extraction for RegisterKyc and DiscloseKyc when creating proof status.

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