feat(payment): add payment detail endpoint and update payment model with order_id and patient_name

feat(appointment): enhance appointment detail page with time formatting and additional info
fix(payment): update payment query to fetch from the correct endpoint and adjust response structure
docs(api): add search parameter to payments API documentation and detail response structure
test(payment): add unit test for MellatGateway to verify null credentials handling

docs/api/admin.md

@@ -600,6 +600,11 @@ List all payments.
 | `limit` | integer | ❌ | Default: 20 |
 | `status` | string | ❌ | `"pending"`, `"paid"`, `"failed"`, `"cancelled"` |
 
+### Query Parameters (تکمیل)
+| Param | Type | Required | Description |
+|-------|------|----------|-------------|
+| `search` | string | ❌ | جستجو در موبایل کاربر، `reference_id` یا `order_id` |
+
 ### Response `200`
 ```json
 {
@@ -607,17 +612,55 @@ List all payments.
   "data": [
     {
       "uuid": "...",
-      "order_id": "CLINICPRO-...",
-      "amount_rials": 500000,
-      "status": "paid",
+      "amount": 500000,
+      "status": "success",
       "gateway": "mellat",
-      "created_at": 1717000000
+      "ref_id": "1234567",
+      "patient_mobile": "0912...",
+      "paid_at": "2026-07-02T09:00:00+03:30",
+      "created_at": "2026-07-02T08:55:00+03:30"
     }
   ],
   "meta": { "totalRecords": 7800, "totalPages": 390, "currentPage": 1 }
 }
 ```
 
+> `amount` بر حسب ریال، `ref_id` همان `reference_id` درگاه، `paid_at` فقط برای پرداخت `success` (بر اساس `updated_at`) و در غیر این‌صورت `null`. تاریخ‌ها ISO-8601.
+
+---
+
+### GET `/api/v1/admin/payments/{uuid}`
+
+جزئیات یک پرداخت. **پاسخ تخت است** (`data` مستقیم آبجکت پرداخت، نه nested).
+
+**Permission:** `ROLE_ADMIN`
+
+### Response `200`
+```json
+{
+  "success": true,
+  "data": {
+    "uuid": "...",
+    "order_id": "ORD-XXXX",
+    "amount": 500000,
+    "status": "success",
+    "gateway": "mellat",
+    "type": "appointment",
+    "ref_id": "1234567",
+    "patient_mobile": "0912...",
+    "patient_name": "علی احمدی",
+    "appointment_uuid": "...",
+    "paid_at": "2026-07-02T09:00:00+03:30",
+    "created_at": "2026-07-02T08:55:00+03:30"
+  }
+}
+```
+
+### Errors
+| Code | HTTP | Description |
+|------|------|-------------|
+| `ERR_NOT_FOUND_001` | 404 | پرداخت یافت نشد |
+
 ---
 
 ## Settlement Management