Add re-analyse button and POST /documents/{id}/reprocess endpoint

Resets status to pending, clears error_message, and re-enqueues the
background AI extraction task. Button is disabled while the document
is already pending or processing; returns 409 in that case from the API.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

changelog/2026-04-17_switch-penpot-to-figma.md

@@ -106,3 +106,17 @@
 - `features/doc-service/app/routers/categories.py` — `POST /documents/categories` now finds similar categories by name (word overlap + SequenceMatcher) and triggers a background task to re-run AI extraction on affected documents, merging new `suggested_categories` into their `extracted_data`
 - `features/doc-service/STATUS.md` — updated endpoints table and filter params table
 - `frontend/STATUS.md` — updated sidebar and documents page sections
+
+---
+
+# 2026-04-17 — Re-analyse button for documents
+
+**Timestamp:** 2026-04-17T00:00:00
+
+**Summary:** Added a Re-analyse button to each document row that re-runs AI extraction on demand. The endpoint resets status to pending, clears any previous error, and enqueues the background processing task. The button is disabled while the document is already pending or processing.
+
+**Files Modified:**
+- `features/doc-service/app/routers/documents.py` — added `POST /documents/{id}/reprocess` endpoint
+- `frontend/src/api/client.ts` — added `reprocessDocument(id)` API function
+- `frontend/src/pages/DocumentsPage.tsx` — added `reprocessMut` mutation and Re-analyse button in document row header
+- `features/doc-service/STATUS.md` — marked reprocess as done, added endpoint to table