fix: Update license validation endpoint and parameter - Change endpoint from /licenses/validate to /licenses/verify - Change parameter from license_key to key to match API specification

Author: VoxHash

src/main/java/com/licensechain/LicenseChainClient.java

@@ -225,11 +225,12 @@ public void deleteLicense(String licenseId) throws LicenseChainException {
      */
     public LicenseValidationResult validateLicense(String licenseKey, String appId) throws LicenseChainException {
         JsonObject request = new JsonObject();
-        request.addProperty("license_key", licenseKey);
+        // Use /licenses/verify endpoint with 'key' parameter to match API
+        request.addProperty("key", licenseKey);
         if (appId != null) {
             request.addProperty("app_id", appId);
         }
-        return post("/licenses/validate", request, LicenseValidationResult.class);
+        return post("/licenses/verify", request, LicenseValidationResult.class);
     }
 
     /**