fix: update ValidateAccountNumberAsync to the v2 account validation path

Sandbox-confirmed both v1 and v2 respond identically right now, but v2 is
the current documented path. Updated the unit test assertion and
docs/COMPATIBILITY.md to match; verified end-to-end against the real
sandbox via the SDK itself, not just the unit test's fake handler.

Author: GREENFONTS

CHANGELOG.md

@@ -16,6 +16,10 @@ own version is independent of Monnify's API versioning.
 * add paycode support — `CreatePaycodeAsync`, `GetPaycodesAsync`, `GetPaycodeAsync`, `CancelPaycodeAsync`, `GetUnmaskedPaycodeAsync` (`IMonnifyCollectionsClient`)
 * add customer wallet support — `CreateWalletAsync`, `GetWalletsAsync`, `GetCustomerWalletBalanceAsync`, `GetWalletTransactionsAsync` (`IMonnifyDisbursementsClient`)
 
+### Changed
+
+* `ValidateAccountNumberAsync` now calls `GET /api/v2/disbursements/account/validate` instead of the `v1` path — the `v1` path still responds identically in sandbox, but `v2` is the current documented path
+
 ### Fixed
 
 * envelope handling now tolerates endpoints (e.g. paycodes) that omit `requestSuccessful` from their response

docs/COMPATIBILITY.md

@@ -69,7 +69,7 @@ Status legend:
 | `IMonnifyDisbursementsClient.GetWalletsAsync` | `GET /api/v1/disbursements/wallet?pageNo=&pageSize=&walletReference=` | **Implemented** | 21 wallets in sandbox; `createdOn` is absent in list items but present on create response |
 | `IMonnifyDisbursementsClient.GetCustomerWalletBalanceAsync` | `GET /api/v1/disbursements/wallet/balance?accountNumber=` | **Implemented** 
 | `IMonnifyDisbursementsClient.GetWalletTransactionsAsync` | `GET /api/v1/disbursements/wallet/transactions?accountNumber=&pageNo=&pageSize=` | **Implemented** | Balance amounts sent as large integers (e.g. 5000000000); `AllowReadingFromString` applied defensively |
-| `IMonnifyVerificationClient.ValidateAccountNumberAsync` | `GET /api/v1/disbursements/account/validate?accountNumber=&bankCode=` | **Implemented** | Free on both sandbox and live |
+| `IMonnifyVerificationClient.ValidateAccountNumberAsync` | `GET /api/v2/disbursements/account/validate?accountNumber=&bankCode=` | **Implemented** | Free on both sandbox and live. Sandbox-confirmed the v1 path also still responds identically, but v2 is the current documented path |
 | `IMonnifyVerificationClient.MatchBvnDetailsAsync` | `POST /api/v1/vas/bvn-details-match` | **Implemented** | Bills the merchant wallet per request |
 | `IMonnifyVerificationClient.MatchBvnToAccountAsync` | `POST /api/v1/vas/bvn-account-match` | **Implemented** | Bills the merchant wallet per request |
 | `IMonnifyVerificationClient.VerifyNinAsync` | `POST /api/v1/vas/nin-details` | **Implemented** | Live environment only; bills the merchant wallet per request |

src/Monnify/Http/MonnifyApiPaths.cs

@@ -22,7 +22,7 @@ internal static class Banks
 
     internal static class Verification
     {
-        public const string ValidateAccountNumber = "/api/v1/disbursements/account/validate";
+        public const string ValidateAccountNumber = "/api/v2/disbursements/account/validate";
         public const string BvnDetailsMatch = "/api/v1/vas/bvn-details-match";
         public const string BvnAccountMatch = "/api/v1/vas/bvn-account-match";
         public const string NinDetails = "/api/v1/vas/nin-details";

tests/Monnify.Tests/Verification/MonnifyVerificationClientTests.cs

@@ -22,7 +22,7 @@ public async Task ValidateAccountNumberAsync_SendsGetWithQueryParams_AndDeserial
         var result = await client.ValidateAccountNumberAsync("0123456789", "044");
 
         Assert.Equal(HttpMethod.Get, handler.Requests[0].Method);
-        Assert.Equal("/api/v1/disbursements/account/validate", handler.Requests[0].RequestUri!.AbsolutePath);
+        Assert.Equal("/api/v2/disbursements/account/validate", handler.Requests[0].RequestUri!.AbsolutePath);
         Assert.Equal("accountNumber=0123456789&bankCode=044", handler.Requests[0].RequestUri!.Query.TrimStart('?'));
         Assert.Equal("Ada Lovelace", result.AccountName);
         Assert.Equal("NGN", result.CurrencyCode);