Add docu for TP loader

Author: VladislavAtanasov95

docs-java/features/connectivity/008-transparent-proxy.mdx

@@ -204,13 +204,56 @@ try {
 
 - `X-Error-Origin` - the source of the error
 - `X-Proxy-Server` - the proxy server (Transparent Proxy)
-- `X-Error-Message` - thorough error message
+- `X-Error-Message` - through error message
 - `X-Error-Internal-Code` - set only when the source of the error is the XSUAA or Destination service.
   The value is the HTTP code returned from one of these services.
 - `X-Request-Id` is sent with the response in all requests, both successful and failed
 
 For more information, see [Troubleshooting](https://help.sap.com/docs/connectivity/sap-btp-connectivity-cf/transparent-proxy-troubleshooting)
 
+## Transparent Proxy Loader
+
+The `TransparentProxy` class is a `DestinationLoader` that enables routing all destination traffic through a single registered gateway host.
+This provides a centralized approach to proxy configuration where all destination requests are automatically routed through the configured gateway.
+
+### Registration Methods
+
+#### Register with Default Port
+
+Register a transparent proxy gateway using the default port 80:
+
+```java
+// Register with default port 80
+// Note: 'gateway.svc.cluster.local' is a sample for a typical Kubernetes Cluster IP service DNS name pointing to the Transparent Proxy [Destination Gateway](https://help.sap.com/docs/connectivity/sap-btp-connectivity-cf/dynamic-lookup-of-destinations)
+TransparentProxy.register("gateway.svc.cluster.local");
+```
+
+
+The host will be verified if it is reachable and must not contain any path components.
+If no scheme is provided, HTTP will be used by default.
+
+#### Register with Custom Port
+
+Register a transparent proxy gateway with a specified port:
+
+```java
+// Register with custom port when Destination Gateway is exposed on a different port via .service.port field in the Destination Custom Resource
+TransparentProxy.register("http://gateway.svc.cluster.local", <port>);
+```
+
+The final URI will be constructed as: `<normalized-host>:<port>`
+
+### Usage Example
+
+```java
+// Register the transparent proxy during application initialization
+TransparentProxy.register("gateway.svc.cluster.local", 8080);
+
+// All subsequent destination requests will be routed through the registered gateway
+// Note: return type is of type TransparentProxyDestination which implements Destination
+Destination destination = DestinationAccessor.getDestination("my-destination");
+```
+
 ## Related Documentation
 
 - [HTTP Client](http-client) - For using destinations with HTTP clients