Form pattern for completing a form in a flexible order

## Context

This came up in a research session in August 2026.

The need to see and fill out a form without being blocked by validation in the first section. Similar to this GOV.UK pattern: https://design-system.service.gov.uk/patterns/complete-multiple-tasks/

## User story

### Form filling
As a **person filling out a form**
I want to complete the sections of the form that I can with the information I have first
So that I can decide what order I fill out the form

Start by reviewing the existing form flow and the linked GOV.UK complete-multiple-tasks pattern. Define how people can view and complete sections in an order that suits them without being blocked by validation in an earlier section; done means the form supports that flexible completion flow.

Written by the indexing model from the issue text.