Address code review feedback

- Use more specific error message: 'Error retrieving operation' vs 'Unable to retrieve operation'
- Fix test name to accurately reflect what is being tested

Co-authored-by: Andrew-Paystack <78197464+Andrew-Paystack@users.noreply.github.com>

Author: Copilot

src/tools/get-paystack-operation.ts

@@ -54,7 +54,7 @@ export function registerGetPaystackOperationTool(
           content: [
             {
               type: "text",
-              text: `Unable to retrieve operation: ${errorMessage}`,
+              text: `Error retrieving operation: ${errorMessage}`,
             },
           ],
           isError: true

test/make-paystack-request-tool.spec.ts

@@ -53,7 +53,7 @@ describe("MakePaystackRequestTool", () => {
       }
     });
 
-    it("should return isError: false (omitted) for successful responses", async () => {
+    it("should omit isError for successful responses", async () => {
       // Mock fetch to return valid JSON
       const originalFetch = global.fetch;
       const validJsonResponse = {