Why: Disabled accounts and mixed credentials could continue to authenticate, while web creation accepted passwords and administrator privileges.
Evidence: SELF receipts /tmp/iam-u3-u2-store-sqlite-green.json, /tmp/iam-u3-u2-store-pg-regression.json, and /tmp/iam-u3-u2-server-sqlite-green.json.
Impact: Adds versioned enable/disable, revokes existing handles, protects the last operable manager, and exposes pending-account/profile APIs. Recovery proposal and legacy-entry closure remain in U3-4.
Refs: IAM U3 r1 stages 4-5; Dev feature/iam-u3-account-directory-recovery