feat: add social media links field to Doctor entity and update API documentation

docs/api/doctor.md

@@ -86,6 +86,13 @@ Get doctor detail with clinics.
       "degree": "specialist",
       "detail": "...",
       "img": [],
+      "social_media": {
+        "instagram": "https://instagram.com/dr.example",
+        "telegram": "https://t.me/dr_example",
+        "aparat": null,
+        "youtube": null,
+        "linkedin": null
+      },
       "satisfaction": "60",
       "point": "3.5",
       "free_turn": "دوشنبه 09:00–13:00",
@@ -216,7 +223,23 @@ Update doctor profile.
 | `uuid` | string (UUID) | Doctor UUID |
 
 ### Request Body (`application/json`)
-Same fields as POST — all optional.
+Same fields as POST (all optional), plus:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `social_media` | object | Keys: `instagram`, `telegram`, `aparat`, `youtube`, `linkedin`. Each value must be a full valid URL or `null`. Any value that fails `FILTER_VALIDATE_URL` is silently stored as `null`. |
+
+```json
+{
+  "social_media": {
+    "instagram": "https://instagram.com/dr.example",
+    "telegram": "https://t.me/dr_example",
+    "aparat": null,
+    "youtube": null,
+    "linkedin": null
+  }
+}
+```
 
 ### Response `200`
 Updated doctor object (same structure as GET single).