audit: 2026-05-30 full-codebase audit — report, issues, docs, runbooks

Full-codebase-audit 2026-05-30 outputs:
- Audit report: 09 - Audits/Full Codebase Audit - 2026-05-30.md
- 81 issue files ISSUE-055..135 (decisions + 1 skipped no-brainer).
- Scanner docs from scratch (was zero): architecture, data model, API ref, payment
  flow, operations runbook + repo README.
- Doc-sync updates across API reference, data models, flows, design system.
- Secret Rotation Runbook (08 - Operations) for the exposed credentials.
- Reusable workflow guide (07 - Development) + .claude/workflows/full-codebase-audit.js.

Issues remain status:open intentionally — the code fixes are uncommitted-then-committed
working-tree changes per repo and aren't "resolved" until merged/deployed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Issues/ISSUE-056-backend-verifypayment-and-paymentcallback-routes-unauthenticat.md

@@ -0,0 +1,40 @@
+---
+issue: 056
+title: "Backend: verifyPayment and paymentCallback routes unauthenticated — payment completion exploitable"
+severity: critical
+domain: Payment
+labels: [security, backend, authentication, webhook]
+status: open
+created: 2026-05-30
+source: Full Codebase Audit 2026-05-30
+---
+
+# Backend: verifyPayment and paymentCallback routes unauthenticated — payment completion exploitable
+
+**Severity:** critical
+**Domain:** Payment
+**Labels:** security, backend, authentication, webhook
+
+## Description
+
+`POST /payments/verify` and `POST /payments/callback` are registered without `authenticateToken` middleware. Additionally, a non-web3 bypass path (`isWeb3Payment === false`) allows marking a payment completed without any verifiable on-chain or provider proof.
+
+An unauthenticated actor can call `/payments/verify` for any payment ID and trigger the completion side-effects (status change, offer acceptance, escrow release) without owning that payment. The callback endpoint is similarly unguarded, allowing fake webhook injection.
+
+## Options
+
+1. Require `authenticateToken` + ownership check on `/verify`; enforce HMAC signature verification on `/callback` as a provider webhook; remove the `isWeb3Payment=false` bypass so completion always requires verifiable proof.
+2. Treat `/callback` as a provider webhook with HMAC only; add auth+ownership for `/verify`.
+3. Remove the non-web3 bypass so payments without a verifiable tx cannot be marked completed.
+
+## Recommendation
+
+Add `authenticateToken` + ownership to `/verify`, enforce HMAC/on-chain verification on `/callback` as a webhook endpoint, and remove the `isWeb3Payment=false` bypass so completion always requires verifiable proof.
+
+## Affected Files
+
+- `backend/src/services/payment/paymentControllerRoutes.ts` — lines 20–21
+
+## References
+
+- [Full Codebase Audit 2026-05-30](../09%20-%20Audits/Full%20Codebase%20Audit%20-%202026-05-30.md) — DEC-23