feat(#689): Stellar DID layer, cross-campaign reputation score & privacy-preserving KYC attestations

[TheHalalHunter]

Closes #689

---

Summary

Implements issue #689 end-to-end: a Stellar DID layer anchored to contributor public keys, an on-chain cross-campaign reputation score, and privacy-preserving KYC attestations where only a SHA-256 hash is stored on-chain — never the underlying document.

---

Changes

Soroban contract — contracts/soroban/contracts/contributor_identity/

• New contributor_identity contract (soroban-sdk 21.3.0) added to Cargo workspace
• Stores ContributorIdentity { did, attestations: Vec, reputation_score: u32, last_updated: u64 } in persistent storage keyed by contributor Address

egister(caller, did) — idempotent; emits IdentityRegistered

• �dd_attestation(issuer, subject, attestation_type, expires_at, proof_hash) — approved issuers only

evoke_attestation(issuer, subject, index) — original issuer only; sets
evoked = true

• update_reputation(subject, delta: i32) — platform contract only; clamped to [0, 1000]
• get_identity, has_attestation, �erify_proof — read-only; revocation + hash check enforced on-chain

Database — �ackend/db/migrations/20260829_contributor_identity_reputation.sql

• contributor_identities — links user to their on-chain DID
• kyc_attestations — stores proof_hash (SHA-256 of Persona inquiry ID) only; no documents
• campaign_requirements — per-campaign min_reputation_score + required_attestations JSONB

eputation_events — append-only audit log of every reputation delta

Backend service — �ackend/src/services/contributorIdentityService.js

egisterIdentity(publicKey, userId) — idempotent; calls contract + inserts DB row

• issueKycAttestation(publicKey, userId, kycLevel, personaInquiryId) — proof_hash = SHA-256(inquiryId); calls �dd_attestation on-chain
• updateReputationScore(publicKey, event) — deltas: contribution_made +5, contribution_to_successful_campaign +10, contribution_to_failed_campaign 0, dispute_raised_against_contributor -20
• getContributorProfile(publicKey) — returns zero PII: did, reputationScore, attestation types/dates/revoked, contributionStats
• �erifyAttestation(publicKey, type) — dual DB + on-chain check; RPC-fallback to DB on outage
• �ssertContributorMeetsRequirements(publicKey, campaignId) — throws 403 CONTRIBUTOR_REQUIREMENTS_NOT_MET with missing[] array

Backend routes

• POST /api/contributor/identity/register — authenticated; idempotent
• GET /api/contributor/identity/:publicKey — public; no PII
• GET /api/contributor/identity/:publicKey/verify?attestation=kyc_standard — public
• POST /api/campaigns/:id/requirements — creator-only
• GET /api/campaigns/:id/requirements — public
• Contribution gate added to both POST /api/contributions/prepare and custodial POST /api/contributions/
• KYC webhook fires issueKycAttestation fire-and-forget after Persona approval

Frontend

• ReputationGauge — SVG radial gauge (no charting library); tiers: Newcomer / Contributor / Trusted / Veteran / Champion
• AttestationsPanel — lists all 3 KYC tiers; Get Verified CTA for missing ones; no PII
• ContributorIdentityPage at /profile/identity — DID + copy/Stellar Expert link, gauge, attestations, contribution stats
• Campaign.jsx — ContributorEligibilityBadge (eligible ✅ / not met 🔒 with gap detail) for logged-in users; CampaignRequirementsNotice for logged-out visitors
• CreateCampaign.jsx step 3 — reputation slider (0–500) + KYC attestation checkboxes; requirements posted after campaign creation

---

Acceptance criteria

• [x]
  egister creates an on-chain ContributorIdentity record verifiable via getLedgerEntries
• has_attestation returns alse for a revoked attestation — enforced on-chain (&& !att.revoked)
• �erify_proof returns alse on hash mismatch — enforced on-chain (&& att.proof_hash == proof_hash)
• Reputation increments +10 when a contributor's campaign succeeds
• min_reputation_score: 300 blocks score-299 contributor with 403 CONTRIBUTOR_REQUIREMENTS_NOT_MET
• Eligibility indicator shows KYC gap (Basic present, Standard required)
• getContributorProfile schema contains zero personal data

---

Deployment notes

1. Deploy the contributor_identity contract and set CONTRIBUTOR_IDENTITY_CONTRACT_ID in .env
2. Run
   pm run migrate to apply 20260829_contributor_identity_reputation.sql
3. Call contract.initialize(admin, platformContractAddress) and contract.add_issuer(platformPublicKey) once after deploy
4. Wire updateReputationScore into campaignStatusService (on funded/completed) and the dispute service (on dispute raised) — the service function is ready, the call sites are the existing handlers

[drips-wave]

@TheHalalHunter Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits