Design the proposal discussion module

## Outcome

A reviewed product and technical design defines how proposal discussion will work without committing implementation to October.

## Scope

- Define actors, permissions, moderation, lifecycle, and abuse controls
- Define data model, API boundaries, notifications, and audit requirements
- Produce UX flows and accessibility requirements
- Document implementation phases, risks, and open decisions

## Acceptance criteria

- [ ] Scope is decomposed into independently deliverable child issues.
- [ ] Architecture and API decisions are linked from this issue.
- [ ] Test, documentation, observability, rollout, and failure behavior are defined where applicable.
- [ ] Epic exit criteria are verified before closure.

## Planning note

This is a 2026 GovTool revamp work item. Its child features and tasks should be added as the scope is refined.

Start by decomposing the listed actors, permissions, moderation, lifecycle, abuse controls, data model, API boundaries, notifications, audit, UX, and accessibility scope into child issues. Define and link the architecture and API decisions, then document implementation phases, risks, open decisions, testing, observability, rollout, and failure behavior. Done means the acceptance criteria and epic exit criteria are verified.

Written by the indexing model from the issue text.