feat: enhance search functionality to include parent names and related fields across categories

docs/api/specialty.md

@@ -86,16 +86,23 @@ List all specialties with pagination (admin view — includes inactive).
 |-------|------|----------|-------------|
 | `page` | integer | ❌ | Default: 1 |
 | `limit` | integer | ❌ | Default: 20 |
-| `search` | string | ❌ | Search in name |
+| `search` | string | ❌ | Matches `name`, `slug`, **or the parent specialty's name** (case-insensitive `LIKE`) |
+| `sort` / `order` | string | ❌ | `sort=id` with `order=asc\|desc`; otherwise ordered by weight then name |
 
 ### Response `200`
 ```json
 {
   "success": true,
-  "data": [ ... ],
+  "data": [
+    { "id": 12, "uuid": "…", "name": "لیزر درمانی", "slug": "laser", "status": 1, "weight": 0,
+      "parent_id": 3, "parent_name": "پوست و مو" }
+  ],
   "meta": { "totalRecords": 50, "totalPages": 3, "currentPage": 1 }
 }
 ```
+- `parent_name` is **admin-list only** — the public `GET /api/v1/specialties` does not return it.
+  It exists because searching by parent can return a child whose parent is not on the current page,
+  so the client cannot resolve the name from its own list.
 
 ### Errors
 | Code | HTTP | Description |