feat(api): implement articlesupplier endpoints, sort reordering, and openapi docs

docs/api/routes/article/supplier/order.md

@@ -0,0 +1,56 @@
+# `PUT /article/{sku}/supplier/order`
+
+Protected. Requires a valid session cookie (`credentials: 'include'`).
+
+Reorder article suppliers
+
+Sets the display sort order of supplier assignments for an article.
+Expects an array of all assigned `articlesupplier` IDs in the desired order.
+
+
+## Path parameters
+
+| Param | Required | Type | Description |
+|-------|----------|------|-------------|
+| `sku` | yes | string | Article SKU |
+
+## Body (JSON)
+
+```json
+{
+  "ids": [
+    12,
+    10,
+    15
+  ]
+}
+```
+
+## Signals
+
+On success, emits SSE signal: `article-<sku>` (see [`GET /events`](../events.md)).
+
+## Response `200`
+
+New order applied
+
+```json
+{
+  "ids": [
+    1
+  ]
+}
+```
+
+## Errors
+
+| Status | Description |
+|--------|-------------|
+| 400 | Invalid supplier order, ids is required, or no company selected — `{"error":"…"}` |
+| 401 | Unauthorized — `{"error":"…"}` |
+| 403 | Not authorized — `{"error":"…"}` |
+| 404 | Article or company not found — `{"error":"…"}` |
+
+---
+
+_Generated from `@openapi` JSDoc. Do not edit by hand — run `npm run docs:api`._