# Task 013: Draft Assembly, Editor, And Generic Preview

Development description: Assemble section scaffolds into a canonical Markdown/MDX draft, provide versioned draft editing, and render a generic rich preview for editor review.

## Implementation Details

- Backend endpoints:
  - `POST /api/articles/{article_id}/draft/assemble`
  - `GET /api/articles/{article_id}/drafts`
  - `GET /api/articles/{article_id}/drafts/{draft_id}`
  - `PATCH /api/articles/{article_id}/drafts/{draft_id}`
- Markdown is the canonical editable draft format.
- Draft assembly includes:
  - Title.
  - Meta title.
  - Meta description.
  - Body Markdown/MDX.
  - FAQ block when applicable.
  - Visual placeholders.
  - Evidence references.
  - Unsupported claim warnings.
- Approval-relevant draft edits create new immutable versions.
- Frontend includes:
  - Draft editor.
  - Generic Markdown/MDX preview.
  - Version selector/history.
  - Unsupported-claim warnings near content.
- The preview is for editor UX and content-shape validation, not target-site build/runtime validation.

## Public Interface

- Editor assembles a draft after production artifacts are ready.
- Editor edits Markdown and metadata.
- Editor views a generic preview.

## Acceptance Criteria

- [ ] TDD pre-requirement: before implementation, write one failing behavior test that assembles a draft from successful section scaffolds through the public API; proceed one draft behavior at a time and record evidence in `Result`.
- [ ] Draft assembly includes all planned sections in order.
- [ ] Draft includes metadata, FAQ, visual placeholders, evidence references, and unsupported claim warnings.
- [ ] Draft version 1 is immutable after approval-relevant edits; edits create a new version.
- [ ] Generic Markdown/MDX preview renders headings, links, tables, images/placeholders, and FAQ.
- [ ] Editor can compare or select draft versions.
- [ ] Draft assembly fails clearly if required section scaffolds are missing.

## Verification

- Run draft assembly API tests.
- Run frontend editor/preview tests.
- Run Docker Compose smoke flow from production artifacts to previewed draft.

## Result

- Status: Pending execution.
- TDD plan: To be filled during execution.
- Red evidence: To be filled during execution.
- Green evidence: To be filled during execution.
- Refactor notes: To be filled during execution.
- Verification output: To be filled during execution.