IMPROVEMENT: Cache Templates, only update the route component, not the entire layout

[Zach Lankton]

Rezact/src/lib/rezact/router.ts

Lines 115 to 128 in 3983220

 if (mod.Layout) { 
   // this will likely work but the fact that we completely clear the 
   // app.innerHTML above means the entire layout will rerender 
   // need to look at "caching" the current layout, checking if the new layout is the same 
   // using a signal to store the actual mod.Page || mod.default render 
   // and just assigninging the new "Page" to that Signal 
   // then only the "children" of the Layout will update as long as the new Layout 
   // is the same as the current Layout 
   render(app, (props) => mod.Layout(props), { 
     Component: mod.Page || mod.default, 
     pageProps: { 
       routeParams: params, 
     }, 
   }); 

[Zach Lankton]

This issue is blocked by #30 .... using signals to swap the Route Components needs to be able to handle Fragments