Contribution attestation UI

[cyberstorm-nisto]

Overview

Add UI for viewing and creating contribution attestations in the didgit.dev web app.

Features

• Display contribution history for authenticated user
• Show attestation status per commit
• Manual attest button for new contributions
• Link contributions to identity attestation

Schema

string repo,string commitHash,string author,string message,uint64 timestamp,bytes32 identityUid

Schema UID (Sepolia): 0x7425c71616d2959f30296d8e013a8fd23320145b1dfda0718ab0a692087f8782