feat(client): dependents section UI with per-row uploads

Add the dependents repeater section to the employee profile form:
zod schema with per-row validation, relationship options, and a
per-dependent document contract wired through dependents-docs and
use-dependent-docs-feedback so every row shows inline national card
and birth certificate upload state. Register the form section and
read-only view, and surface blocking document warnings in the review
step. Includes education rows adopting the shared feedback helpers.