Extend PATCH /category/:id to also move (parentId) alongside rename.

PATCH now accepts name (rename, re-slugify) and/or parentId (move under a
new parent, cycle/self guarded), merging both results. Renames the PATCH
docs file to category/update.md and regenerates API docs.

docs/api/openapi.json

@@ -1140,14 +1140,14 @@
         "tags": [
           "Category"
         ],
-        "summary": "Rename category",
-        "description": "Renames a category the user is authorized for (updates name and re-slugifies in the company default language).",
+        "summary": "Update category (rename or move)",
+        "description": "Updates a category the user is authorized for.\n`name` renames the category (re-slugifies in the company default language).\n`parentId` moves it under a new parent (cycle/self → `Invalid parent`).\nEither `name` or `parentId` (or both) is required.\n",
         "security": [
           {
             "cookieAuth": []
           }
         ],
-        "x-markdown": "category/rename.md",
+        "x-markdown": "category/update.md",
         "parameters": [
           {
             "in": "path",
@@ -1165,16 +1165,17 @@
             "application/json": {
               "schema": {
                 "type": "object",
-                "required": [
-                  "name"
-                ],
                 "properties": {
                   "name": {
                     "type": "string"
+                  },
+                  "parentId": {
+                    "type": "integer",
+                    "description": "New parent category id"
                   }
                 },
                 "example": {
-                  "name": "Renamed category"
+                  "parentId": 3
                 }
               }
             }
@@ -1182,7 +1183,7 @@
         },
         "responses": {
           "200": {
-            "description": "Renamed category",
+            "description": "Updated category (renamed and/or moved)",
             "content": {
               "application/json": {
                 "schema": {
@@ -1193,7 +1194,9 @@
                       "required": [
                         "id",
                         "name",
-                        "slug"
+                        "slug",
+                        "parentId",
+                        "sort"
                       ],
                       "properties": {
                         "id": {
@@ -1204,6 +1207,12 @@
                         },
                         "slug": {
                           "type": "string"
+                        },
+                        "parentId": {
+                          "type": "integer"
+                        },
+                        "sort": {
+                          "type": "integer"
                         }
                       }
                     }
@@ -1213,7 +1222,7 @@
             }
           },
           "400": {
-            "description": "Validation error (name required)",
+            "description": "Validation error (name or parentId required, or invalid parent)",
             "content": {
               "application/json": {
                 "schema": {