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

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

@@ -21,6 +21,7 @@ Assigns a supplier to an article with optional purchase price, stock, and suppli
   "sku": "MET-44910",
   "pu": 1,
   "stock": 140,
+  "sort": 0,
   "netPrice": 4.2,
   "taxId": 1
 }
@@ -44,6 +45,7 @@ Created supplier assignment
     "sku": "…",
     "pu": 1,
     "stock": 1,
+    "sort": 1,
     "priceId": 1,
     "price": {
       "net": 1,

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

@@ -27,6 +27,7 @@ List of suppliers linked to the article
       "sku": "…",
       "pu": 1,
       "stock": 1,
+      "sort": 1,
       "priceId": 1,
       "price": {
         "net": 1,

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`._

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

@@ -43,6 +43,7 @@ Updated supplier assignment
     "sku": "…",
     "pu": 1,
     "stock": 1,
+    "sort": 1,
     "priceId": 1,
     "price": {
       "net": 1,