RustyLee: Starts Heart organ processing

Activates the Heart organ's main command processing loop by calling its `start` method.

Replaces the previous placeholder `run_loop` method with the functional `start` method. The `start` method now takes a mutable reference to `self`, which enables it to operate as a long-running process without consuming the `Heart` instance.

src/rustylee/src/organs/heart.rs

@@ -10,12 +10,6 @@ pub struct Heart {
     feedback_to_brain_tx: mpsc::Sender<BrainMessage>,
 }
 
-impl Heart {
-    pub(crate) fn run_loop(&mut self) {
-        todo!()
-    }
-}
-
 impl Heart {
     pub(crate) fn new(id: u32, rx: Receiver<OrganCommandEnvelope>, tx: Sender<BrainMessage>) -> Self {
         Self {
@@ -24,11 +18,9 @@ impl Heart {
             feedback_to_brain_tx: tx,
         }
     }
-}
     
-impl Heart {
     #[instrument(skip(self), fields(heart_id = self.id))]
-    pub fn start(self) {
+    pub fn start(&mut self) {
         info!("Heart listener active");
 
         while let Ok(envelope) = self.brain_command_rx.recv() {

src/rustylee/src/organs/organ_factory.rs

@@ -44,7 +44,7 @@ impl OrganFactory {
 
         thread::spawn(move || {
             let mut heart = Heart::new(id, brain_command_to_organ_rx, feedback_to_brain_tx);
-            heart.run_loop();
+            heart.start();
         });
 
         socket