feat: add social media fields to Clinic entity and update API documentation

docs/api/clinic.md

@@ -52,6 +52,7 @@ Create a new clinic.
 | `specialties` | integer[] | ❌ | Specialty IDs |
 | `doctor_services` | integer[] | ❌ | Service IDs |
 | `insurance` | integer[] | ❌ | Insurance IDs |
+| `social_media` | object | ❌ | Social media URLs — keys: `instagram`, `telegram`, `aparat`, `youtube`, `linkedin`. Values are validated as URLs; invalid/empty values are stored as `null`. |
 
 ### Response `201`
 ```json
@@ -120,6 +121,13 @@ Get clinic detail.
       "logo": "/uploads/clinics/logo/...",
       "clinic_logo": "/uploads/clinics/logo/...",
       "images_clinic": [{ "url": "/uploads/clinics/gallery/..." }],
+      "social_media": {
+        "instagram": "https://instagram.com/clinic.example",
+        "telegram": "https://t.me/clinic_example",
+        "aparat": null,
+        "youtube": null,
+        "linkedin": null
+      },
       "caption": "توضیحات کلینیک",
       "list_bime": [],
       "specialties": [{ "uuid": "...", "id": "1", "name": "قلب", "parent": null }],