- Extract shared authentication logic into utils/auth/authCore.js
- Replace enableBasicAuth/enableAuthCode flags with clear authScope enum (ADMIN/USER/EITHER)
- Move all auth-related files into utils/auth/ subdirectory
- Eliminate duplicated admin auth logic between _middleware.js and dualAuth.js
- Fix: user session no longer grants access to admin-only endpoints
- Fix: dualAuth no longer bypasses authCode when admin is not configured
- Update all 17 import references across the codebase
- Preserve original function signatures (userAuthCheck, dualAuthCheck) for zero caller changes