refactor(controller): use state to find available port range

src/state.rs

@@ -88,8 +88,8 @@ impl StateManager {
         self.0.borrow_mut().instances.insert(project_name, state);
     }
 
-    pub fn remove(&self, project_name: &str) -> Option<InstanceState> {
-        self.0.borrow_mut().instances.remove(project_name)
+    pub fn get_highest_used_port(&self) -> Option<u16> {
+        self.0.borrow().instances.values().map(|i| i.port).max()
     }
 }