rename to smartpack n smartunpack

examples/smartreceive_example.rs

@@ -1,4 +1,4 @@
-use msghandler::{smartreceive, SmartreceiveOptions};
+use msghandler::{smartunpack, smartunpackOptions};
 
 fn main() {
     // Simulated message JSON (received via any transport)
@@ -40,9 +40,9 @@ fn main() {
         ]
     }"#;
 
-    let options = SmartreceiveOptions::default();
+    let options = smartunpackOptions::default();
 
-    match smartreceive(msg_json_str, &options) {
+    match smartunpack(msg_json_str, &options) {
         Ok(envelope) => {
             println!("=== Envelope Received ===");
             println!("Correlation ID: {}", envelope.correlation_id);