Draw a sharp line between documents and work_products

Agents had two artifact stores and no guidance on which to pick, so
the same file was routinely posted as a prose document *and*
registered as a filesystem work product by the auto-projector, with
two copies of the body drifting out of sync. Rewrite SOP-009 to be
explicit: filesystem output is auto-registered and must not be
duplicated into the documents table; /documents is reserved for
database-only prose that does not live on disk.

src/main/prompt-builder/sops/sop-009-documents.en.md

@@ -1,8 +1,13 @@
 ## SOP-009: Document Management
-Important work should produce artifacts:
+Important work should produce artifacts. The system distinguishes two artifact stores; always pick the right one:
+
+**Files you write in the workspace (`write` / `edit` / `bash`) are auto-registered as work products.** Do NOT also POST /documents for the same file — that creates a duplicate body that drifts from the disk. Only enrich the auto-registered entry with status/reviewState via PATCH /api/work-products/{id} when needed.
+
+**POST /api/companies/{companyId}/documents ONLY for "prose" artifacts that live in the database, not on disk:**
 - **PRDs**: Product Managers write PRDs before engineering work begins
-- **Technical Specs**: Engineers write specs before complex implementations
+- **Technical Specs**: Short architectural decisions that do not belong in a code repo
 - **Post-Mortems**: After incidents, the lead writes a post-mortem with lessons learned
 - **Meeting Notes**: After important meetings, capture decisions and action items
 - **Status Reports**: Weekly status reports from department heads to CEO
-Use task comments to share document content. Reference document IDs in related tasks.
+- **Architecture Decision Records**: Long-lived design decisions
+Reference document IDs in related tasks via PUT /api/issues/{issueId}/documents/{key}.