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

docs/api/doctor-service.md

@@ -53,17 +53,22 @@ List all services with pagination (admin view).
 |-------|------|----------|-------------|
 | `page` | integer | ❌ | Default: 1 |
 | `limit` | integer | ❌ | Default: 20 |
-| `search` | string | ❌ | Search in name |
+| `search` | string | ❌ | Matches `name`, `slug`, **or the related specialty's name** (case-insensitive `LIKE`) |
 | `specialty_id` | integer | ❌ | Filter by specialty |
 
 ### Response `200`
 ```json
 {
   "success": true,
-  "data": [ ... ],
+  "data": [
+    { "id": 7, "uuid": "…", "name": "بوتاکس", "slug": "botox", "status": 1, "weight": 0,
+      "specialty_id": 3, "specialty_name": "پوست و مو" }
+  ],
   "meta": { "totalRecords": 30, "totalPages": 2, "currentPage": 1 }
 }
 ```
+- `specialty_name` is **admin-list only** — the public `GET /api/v1/doctor-services` does not return it.
+- Services without a specialty are still listed (the join is a `LEFT JOIN`).
 
 ### Errors
 | Code | HTTP | Description |