feat: update wallet openapi, client methods and readme

Author: fatemefallah

README.md

@@ -189,7 +189,7 @@ Manage user balances, expenses, and refunds.
 
 ```python
 from basalam_sdk import BasalamClient, ClientCredentials
-from basalam_sdk.wallet.models import SpendCreditRequest, RefundRequest
+from basalam_sdk.wallet.models import SpendCreditRequest, SpendSpecificCreditRequest, RefundRequest
 
 auth = ClientCredentials(client_id="...", client_secret="...")
 client = BasalamClient(auth=auth)
@@ -203,7 +203,23 @@ expense = client.create_expense_sync(
     request=SpendCreditRequest(
         amount=1000,
         reason_id=1,
-        reference_id=456
+        reference_id=456,
+        description="Payment for order #456",
+        types=[1, 2],
+        settleable=True
+    )
+)
+
+# Create an expense from a specific credit
+expense = client.create_expense_from_credit_sync(
+    user_id=123,
+    credit_id=789,
+    request=SpendSpecificCreditRequest(
+        amount=1000,
+        reason_id=1,
+        reference_id=456,
+        description="Payment for order #456",
+        settleable=True
     )
 )
 
@@ -231,6 +247,7 @@ refund = client.create_refund_sync(
 | `get_balances()`          | Get user's balances                | `user_id`, `filters`, `x_operator_id`                                         |
 | `get_transactions()`      | Get transaction history            | `user_id`, `page`, `per_page`, `x_operator_id`                                |
 | `create_expense()`        | Create an expense                  | `user_id`, `request`, `x_operator_id`                                         |
+| `create_expense_from_credit()` | Create expense from specific credit | `user_id`, `credit_id`, `request`, `x_operator_id`                        |
 | `get_expense()`           | Get expense details                | `user_id`, `expense_id`, `x_operator_id`                                      |
 | `delete_expense()`        | Delete/rollback expense            | `user_id`, `expense_id`, `rollback_reason_id`, `x_operator_id`                |
 | `get_expense_by_ref()`    | Get expense by reference           | `user_id`, `reason_id`, `reference_id`, `x_operator_id`                       |