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-104-backend-bcrypt-native-addon-alongside-used-bcryptjs.md

@@ -0,0 +1,38 @@
+---
+issue: 104
+title: "Backend: native bcrypt addon present alongside bcryptjs — unnecessary build toolchain dependency"
+severity: medium
+domain: Dependencies
+labels: [backend, dependencies, cleanup]
+status: open
+created: 2026-05-30
+source: Full Codebase Audit 2026-05-30
+---
+
+# Backend: native bcrypt addon present alongside bcryptjs — unnecessary build toolchain dependency
+
+**Severity:** medium
+**Domain:** Dependencies
+**Labels:** backend, dependencies, cleanup
+
+## Description
+
+`backend/package.json:67` includes `bcrypt` (native C++ addon, requires build toolchain) alongside `bcryptjs` (pure JS). Code uses `bcryptjs`. The native addon adds unnecessary native build complexity and is an unused dependency.
+
+## Options
+
+1. Remove `bcrypt` (keep `bcryptjs`) after confirming no imports and no migration need.
+2. Standardize on native `bcrypt` instead (faster) and migrate hashes-compatible.
+3. Leave both.
+
+## Recommendation
+
+Confirm `bcryptjs` is the sole hasher and remove native `bcrypt` to drop the build toolchain requirement. Hashing libs are sensitive — verify before removing.
+
+## Affected Files
+
+- `backend/package.json:67`
+
+## References
+
+- [Full Codebase Audit 2026-05-30](../09%20-%20Audits/Full%20Codebase%20Audit%20-%202026-05-30.md) — DEC-53