4 plans in 4 sequential waves covering:
- Plan 01 (TDD): openai install, extract-text.ts, field-placement.ts, aiCoordsToPagePdfSpace unit test
- Plan 02: POST /api/documents/[id]/ai-prepare route with all guards
- Plan 03: UI wiring — aiPlacementKey in FieldPlacer, AI Auto-place button in PreparePanel
- Plan 04: Unit test gate + human E2E verification checkpoint
Satisfies AI-01, AI-02. Completes v1.1 Smart Document Preparation milestone.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
