Task: Promote simplified password lifecycle

Identity

Promote the accepted password-lifecycle facts from feature task 20260902-registration-invalid-params-59f94692 and merge commit 029c8c6a59215cb6c3f8d7f126c4313730b2abb2 into canonical project memory.
Reconcile AUTH-001, the decision index, system overview, business rules, current state, and evidence index.
Run the task-aware project-document gate and complete repository verification from a base commit that already contains the source task record and evidence.

Record the user's explicit product decision: passwords require a non-empty value but have no application-level length restriction, and first-login forced password changes are disabled.
Preserve voluntary password change, administrator reset, session revocation, account roles, owner isolation, route grants, audit, dashboard behavior, and ERP safety boundaries.
Treat the historical must_change_password column as compatibility-only; do not add a destructive migration.
Do not restart or deploy services, mutate live accounts/database rows, access ERP, or send data externally.

Accepted the source task's promotion candidates without semantic conflict because the user directly confirmed the product behavior.
Updated AUTH-001, the decision index, system overview, business rules, current state, and evidence index.
Recorded merge commit 029c8c6a59215cb6c3f8d7f126c4313730b2abb2 and this integration task under Integrated Through.
No runtime, database, ERP, external-system, deployment, or service-process state was changed.

Source merge verification: repository check 10/10, control-plane 153/153, legacy 260/260, TypeScript check/build, JavaScript syntax, and diff checks passed on integrated main.
check_project_docs.py: passed.
check_doc_drift.py --task-id 20260902-promote-password-flow-c81d42: passed for all canonical writes.
git diff --check: passed.
node --run check:repo: 10/10 passed after canonical integration.
node --run check: passed after canonical integration.
node --run test:control-plane: 153/153 passed after canonical integration.
node --run test:legacy: 260/260 passed after canonical integration.
node --run build: passed after canonical integration.

Restart or redeploy the standard service only under separate explicit authorization before relying on the new backend behavior in the running process.