security: redact admin credentials from public documentation

Removed specific admin email addresses and password information.
Admin credentials should only be stored in secure local files
outside version control.

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

BACKEND_FRONTEND_MAPPING.md

@@ -13,10 +13,10 @@
 - **Login**: https://agenticgovernance.digital/admin/login.html
 - **Dashboard**: https://agenticgovernance.digital/admin/dashboard.html
 
-**Admin Credentials** (Production):
-- Email: `admin@agenticgovernance.digital`
-- Password: Set in production database (test via API login)
-- Alternative: `admin@tractatus.local`
+**Admin Credentials**:
+- Contact system administrator for credentials
+- Login credentials stored securely (not in version control)
+- Password reset utility available locally only
 
 ---