Users: employeeId auto-generated from role prefix (TCH/MAN/ACC/MGR/SUP/AUD/ADM)
followed by next sequential number; shown read-only in edit form, removed
from create form. Cost Centres: new code field (SITE-001 ...) added to
Vessel model with migration + backfill; auto-generated on create, read-only
in edit. Vendors and Accounts: code/vendorId inputs pre-filled with the
next suggested ID (VND-001, ACC-001) from the server page; user can override
with any PREFIX-NUMBER format, validated by regex.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
