Refactor application ports to 12000 for backend and 12001 for frontend; update documentation and configuration files accordingly

Co-authored-by: Copilot <copilot@github.com>

frontend/app/static/app.js

@@ -79,6 +79,6 @@ document.addEventListener("DOMContentLoaded", () => {
       } catch (e) {
         console.error("Video polling error:", e);
       }
-    }, 5000);
+    }, 12001);
   }
 });